I'd argue since the beginning not just 20 years.

without id, gaming as we know it wouldn't exist today. FPS games, competitive shooters, hell even Valve itself likely wouldn't exist without id software. goes even beyond that. you could even go as deep as the modding community and all the games that have come from that. the majority of modders got their start with id games. Many rockstar game devs got their start at id or via an id product.

They released Wolfenstein 3D in 1992 - 34 years ago. And pretty much everything they've released since has been great.

I'm going to go sit down now because my bones hurt thinking about that fact.

that don’t hold their own

It never was like that. Studios that do badly are never gutted, not as far as I've seen from online reports.

I think the reason why studios are gutted after success is that it's almost guaranteed that the money will keep flowing even after they are fired, BECAUSE of the success.

If you make a game and it sucks the company can't afford to fire you because they don't have guaranteed cash flow regardless if you're there or not.