I understand that the Mon have gotten stronger, and ill admit that there are arguments to be made for a lot of the bans. However, I fundamentally disagree with the idea that "this pokemon is unkillable" or "nothing can switch in to this". There are over 1000 pokemon in this game and y'all really expect me to believe that not one of them can KO gliscor or gholdengo? A certain ice/ground type pokemon would like to know your location. I mean for goodness sake people, gliscor doesn't even have roost anymore, it can only heal by spamming protect, the move taunt literally exists
I think my biggest issue is that nobody wants to do any experimentation, or search through the pokédex to find mons that will deal with the problem at hand. Everyone just wants to keep using iron valiant and great tusk. In previous gens it was common for pokémon to be tiered as UU or lower, but still have viability in OU. But now in Gen 9, that is almost unheard of which I think is absolutely crazy.
What it feels like to me, is that everyone in OU is using the same 6-7 mons, and crying about something being broken when the opponent uses a niche pokemon that deals with the OU staples
This is a massive oversimplification of what the situation is like atm.
Gliscor arguably would not even run Roost this generation because on top of how tightly contested its moveslots are, one of its major appeals right now is how easily it makes progress with the turns it naturally buys in front of things that don't break it, which Roost is redundant with since even if Gliscor heals in front of a Pokemon, it's either just sitting there playing chicken or over-healing an already-winning match up where it could do something like lay a Spike, Knock Off an item, or safely U-Turn into a more directly offensive teammate. Simply presuming that Gliscor is worse because it lost Roost is to ignore the Metagame it finds itself it or things it DOES have over previous generations such as Terastalization, access to Spikes, and a much better Hazard-survival profile in a Meta with very few Hazard removers (exacerbated by one of its better teammates).
The issue is not the fact that Gliscor or Gholdengo cannot be KO'd: Great Tusk is lauded as the best Spinner specifically because it's the one with the best match-up against Gholdengo without compromising itself. The issue is that these Pokemon are so constrictive on the state of the Meta due to being so proficient in their roles that a Pokemon must be able to overcome that high bar if it wants to play in the tier. Consider Gholdengo's typing and ability: 12/18 types on the chart are resisted or immuned by it, and its ability completely shuts down anything that isn't direct damage from targetting it. This basically means if your Pokemon does not have access to a specific 1/3 of the type chart AND half-decent offenses, Gholdengo uses it as food, something you don't want to allow a Pokemon with Nasty Plot, solid Bulk, >130 on its primary offense, and one of the most colorful movepools in OU (MiR is just Draco Meteor but without total crippling for example). Gholdengo without having to tailor itself any major way heavily pressures almost every defensive Pokemon even before considering offensive match-ups it's afforded by its resistances and set-up opportunities therein.
Plenty of Pokemon exist that can KO Gholdengo or Gliscor, such as Great Tusk, Kingambit, Cinderace, and Iron Moth for the former, but the problem that arises is that pool is narrow and thus heavily limits/dictates what playstyles you can make work without a massive weakness to these two, while they in turn match-up into so much of the Pokedex (much less the OU viable roster) that they don't present significant opportunity cost to discourage their presence on teams in turn.
People keep using Iron Valiant or Great Tusk or whatever current OU staple you point to because they work. Fixing a bad Gliscor match-up isn't as simple as slapping Mamoswine on the team: dropping Great Tusk means losing the tier's best Hazard Removal/Glue option (and preventing Hazard removal is already what those two mons want technically), while using it with GT means having to account for a massive weakness overlap in the shared Ground typing while the tier has other big threats like Ogerpon, Manaphy, and to a lesser extent things like Rillaboom. Most of the rest of the Pokedex has been "experimented" with and found to simply not be as efficient in the Metagame at large even if they deal with these particular Pokemon, and having to run otherwise-unviable Pokemon to improve a match-up at the top at the expense of the dozens of other Pokemon in the tier is frequently viewed as a sign of an unhealthy state (most infamous recently is Water Absorb Seismitoad into Dracovish in Gen 8).
To be blunt, saying "Search the Pokedex" is passing the buck and burden of proof when making the argument that goes against current consensus. It doesn't specify any examples of Pokemon that fulfill the role you claim exists but no one is using nor demonstrate that they are effective and simply underexplored. Maybe a Pokemon fitting these descriptions is in the roster, but the way this post argues does nothing to present a solution, just say "figure something else out." Several Pokemon that make UU by usage still see play in OU, such as Heatran post-Bloodmoon, Greninja, Garganacl, and the on-the-rise Alomomola, the difference being most of these Pokemon are teams adapting to trends, not to literally a single Pokemon.
What it feels like to me, is that everyone in OU is using the same 6-7 mons, and crying about something being broken when the opponent uses a niche pokemon that deals with the OU staples
To this I direct you to the infamous carkoala vs "Sylveon is so cute" game in SCL recently, in which 70/131 turns, more than half the game was more or less just two Gliscor sitting on each other and PP Stalling because even amongst the 9 Pokemon on both teams (which did not include any other Survey subjects besides the mellowing-out Kingambit), Gliscor into Gliscor was the safest/most-optimal state to keep things in until it literally had no move left to use. This isn't crying about the opponent using a niche mon, both players were using what is considered to be a highly effective and centralizing member of the tier and everyone agrees it turns the match into an unappealing state of affairs.
I don't know what you're referring to about Volcarona not being seen "throughout the entire Suspect timeframe" since the contention was Volcarona being Quickbanned, there was no Suspect for it to be encountered in. It's also disingenuous to cite this while talking about the process as "all of a sudden" when Volcarona has historically been one of the most contentious presences in OU despite never being pushed to a ban (it's been referred to as the "match-up moth" in several contexts) and this was simply the generation where the changes were too heavily pushing those problem traits (affording a Pokemon that sweeps if you generate a set-up window much easier set-up options). You have a case to argue that the quickban was mishandled in terms of the process (Volc being one of the few subjects to face a Quickban without being a featured Survey option), but that topic has been covered and in hindsight is generally considered to be the ideal result reached by a mistaken/poor course at the time.
And at risk now of feeling like a call out, your account is not much older than your first reply on this subject, despite trying to make the imposing promise of "never playing OU again" if a very-disliked defensive Pokemon is banned (Defensive specified because they take a lot more work and argument to demonstrate a "broken" influence over a kill-everything attacker like Flutter Mane, Bundle, or Bloodmoon). I take you at your word that you play OU a lot, but for that reason I think this post low quality because you should be arguing from knowledge the rest of the playerbase is discussing already, or able to demonstrate play options that support your uncommon position rather than dismissively call for other players to find it because you assume it to exist.
(and Mamo on the non balloon sets! 
)
with quite a lot of success. Expert belt, it easily OHKOs lures the following: Gliscor, Gholdengo, Great Tusks, Hatterene and it hits like a truck while outspeeding a big bunch of falks. Also great typing.
