Recently Hytale, a would-be Minecraft successor, released early access. That project started around a decade ago as something of an indie project, was purchased by Riot, then cancelled by Riot, then recently sold back to the original project people... who basically undid a lot of fruitless work done by Riot and... as I said... now released as early access. A well received early access as far as I can tell.

I wonder why we don't see more indie games and new developers that are more able rising to challenge what look like dysfunctional incumbents?

I'll be the first to admit that I don't know anything about that industry, but it seems like there's space to make progress for newcomers.