Hyper Offense is naturally a very inconsistent playstyle. You either know you're winning a few turns in or you know you're losing a few turns in for the most part. They can be prone to status, misses, occasionally missing rolls, etc. and when every turn an HO team has is as precious as it is you can't afford to have too many bad turns. Moreover, they can be super matchup-dependent and a lot of stuff that gives HO a decent amount of trouble (mostly Ash-Greninja, which is enough of a danger that its only truly good long-term countermeasure that fits on these teams is Mega Gyarados) is also pretty prominent in this meta. Zygarde getting banned also hurt HO a lot because Zygarde provided a lot of role compression for such teams due to its amazing coverage with just one moveslot, access to strong priority, access to several amazing setup moves, and excellent bulk with a good defensive typing that enabled so many setup opportunities. Zygarde was one of the most consistent things commonly found on this otherwise-inconsistent playstyle.What has caused playstyles such as HO and TR to fall down in popularity and usage?
Trick Room as a whole was almost always quite bad, though. Unlike Drizzle/Sand Stream you don't have stuff that automatically sets Trick Room nor do you have items to extend it, so you almost always dedicate at least two slots on full TR teams to just stuff that sets Trick Room and you're dedicating a turn to getting hit, set up on, statused, or what have you every time you want to set Trick Room. Dedicating two near dead-weight slots to just getting it up is problematic on its own, and a lot of the stuff that abuses Trick Room - mostly Stakataka, which sets its own, and Alolan Marowak, who during its stint in OU was more commonly used for its defensive utility - has since fallen out of favor either because they have an atrocious defensive typing and can't even OHKO or even 2HKO some crucial threats or need to dedicate yet another precious Trick Room turn to setting up to truly hit as hard as possible. Offensive Trick Room Magearna is still technically viable, but that set has fallen out of favor because of how good Shift Gear sets are by comparison. The really good Trick Room setters are the ones that can abuse their own Trick Room, and even those kinds of setters are just kinda outclassed by other threats or other sets.