I'm also not sure we should be counting Kartana as "potentially capable of taking special hits" even if it does resist.
Despite the low bulk, Kartana's typing is good enough where with investment it can actually live some special hits and threaten back 1hkos. In both Smogon and VGC, specific investment to live certain hits is not uncommon, expecially if it lets it come in and delete a lategame wincon like say, Kyogre or Xerneas.
I got ninjad by
Cuddly but you get the jist of it.
Choice Specs Tera-Normal Punk Rock Boosted Boomburst
252+ SpA Choice Specs Punk Rock Toxtricity Boomburst vs. 252 HP / 4 SpD Toxapex: 328-387 (107.8 - 127.3%) -- guaranteed OHKO
The new Dracovish
So allow me to do one simple remark about all this crap.
It's pointless. I can go pick up the OU tier list, and i don't even have to go further than A rank to see a bunch of pokemon that would make much better use than literally anything that can be proposed.
You (not ad hominem, just "you" as reader generically) have to understand that pokemon is not a 1v1 game, it's a 6v6 (or 4v4 or 3v3 depending on format).
While using Terastalyze to make a generic lower tier trashmon good against higher tier ones may seem funny on paper, there's always the problem you're investing a team slot + the entire mechanic on it instead of... on a good pokemon instead!
Why would you bring Toxtricity or Ursaluna when you could instead have good pokemon and have the flexibility to Terastalyze Tapu Koko or Landorus-T or Weavile or Urshifu or <insert list from OU>, or in case of Ubers, instead of G-darmanitan or Mewtwo or Arceus or whoever the heck you want?
What is the point to invest a entire team slot + basically mandate the mechanic to be used on that pokemon when you could instead use a good one? You want to make a youtube video about a PU pokemon trashing on low ladder Ubers? Sure by all means do it, that's what certain youtubers do half of the time but I'll be more impressed when you actually do that in a tournament or in VGC, which surprise surprise, these same youtubers bring normal team comps to because they actually like winning, expecially if there's money involved.
On the topic of VGC, VGC is the *only* place where you
*may* see dedicated Terastalyze pokemon, due to the nature of the format. For the same reason you see Blast Burn Charizard, or full inaccurate/2 turn moves Dialga, Fly Landorus-Therian and Thundurus, etc, the nature of the format lets you actually leave behind 2 pokemon, so if you have a pokemon that mandates using the mechanic on them but it's a bad matchup, you aren't actually penalyzed.
VGC even saw things like double-mega comps in previous gens, for same reason, you were not penalyzed by having a pokemon that can't function if the other is there, because you can pick which to bring and both serve their purpose in the 4v4 scenario.
But when it comes to Smogon format, you'd be effectively "wasting" a team slot on top of nerfing your composition by not having the versatility the mechanic offers. The payout has to be absolutely hilarious for this to be worth it. There's a reason after all for which for example Mega Beedrill or Mega Pidgeot was never seen in OU: you invested the mega slot in a pokemon that cannot function without it, and gave up the option to run... idk, an actually good mega. Meanwhile Mega Mawile and Mega Sableye actually saw play (Sableye even getting banned in one gen) because the trade off for dedicating the team slot + gimmick to that pokemon was so good it was worth using a pokemon that cannot function without it.
Sure Tera/Dynamax are different from megas since "everyone can use them", but that only makes the problem worse, as instead of 10 competitors, you have a entire tier (or more) of better users than <insert generic lower tier trashmon>.
