Smogon strives for the most competitive metagames possible
That is why I love gen 8 OU, sure games lasted ages and various other lengths sometimes but it was a metagame that rewarded good play actively that was competitive and allows all types of team styles, which is what Smogon metagames strive for. Gen 8 is symbolic of that. I am someone who enjoys gen 8 for all the stuff you can run, even if it got stale for people it feels a lot like ADV where you can get away with running a ton of wacky stuff in gen 8 OU.
Ideally this is what Smogon is striving for, gen 8 was a very competitive meta and pretty healthy for the most part, even if people are split on enjoyment. Gen 9 is far from being anywhere near competitive, partially due to tera the problems indirectly escalated by it like the hazard problem and other general broken stuff too.
Say what you want about gen 8, but its a very competitive metagame.
All good points. But I do want to point out that a game doesn't have to be highly predictable to be competitive. We might define a competitive game as something along the lines of "skilled and experienced players who use their knowledge and strategic thinking to outplay their opponents". Pokemon is an inherently unpredictable game. If it wasn't, we wouldn't have critical hits, and static paras, and 10% ice beam freezes. Part of the competitive skill in Pokemon is being able to play around these random events and unpredicted circumstances and still come out on top. Tera adds to the unpredictability, but being able to play around tera is a skill. So I don't think that tera in and of itself is necessarily making this gen less competitive, unless it's on the overbearing wincons that people are already calling to be banned. The hazard issue and broken stuff (Kingambit) are problematic certainly.