There are a literal crapton of rpgmaker rpgs on steam, for anybody who likes rpgs but doesn't obsess over graphics (ie. me). BG3 will have absolutely no effect on that market. Unity shenanigans might, but the success of BG3 won't harm the indy market for rpg at all. It might even help a bit, since there will possibly be some new fans willing to tentatively fork over dollars for turn based rpg after they play BG3.

I'm sure BG3 will cause changes in the AAA space, but that's because all the AAA producers try to copy anything that succeeds. 95% of everything is crap, so most of the AAA "copies" will be crap, but maybe there will be a good one two.

In any case, it looks like some AAA games are doing themselves in without help from BG3. For instance... what the hell happened with Diablo 4?