To summarize the actual tweets/comments/etc that these videos (there are multiple) are panicking about.
Smaller studios aren't going to be able to replicate the scale and complexity of BG3. So people shouldn't be using BG3 as the bar to compare future titles/RPGs from other studios going forward. Larian is comparable in size (or even larger) to Bethesda when they released Skyrim, and no one has been able to compete directly with Skyrim either.
Not all games and RPGs need to be as complex and long as BG3. Expecting open-ended, 100 hour-long RPGs for every future game/RPG isn't realistic. Not all games require that scope, it's rare to get such a budget for this type of game, and even if you did, most companies won't be able to replicate the game in a meaningful way. Just like how companies other than Rockstar would struggle to replicate the scale of games like GTA and RDR.
There, I've summarized multiple 20 min videos. Just without all the hand-waving and drama.