- Halo Infinite's slipstream engine turned into spaghetti code due to 343's terrible employee cycling, most of the directors left around the same week, and now they're rehiring a brand new team made up of devs with Unreal Engine experience because the old engine would take too long to fix.
- The terrible console performance and engine woes of CD Project Red's Cyberpunk 2077 that almost led to the company being sued into hell led to them abandoning their own engine and switching to Unreal Engine for their next game.
Bethesda Game Studios is getting there.
I don't know about indie games as much, but I know Distant Worlds 2 got bit by its exotic engine.
I guess at the low end (indies), you can design something lean that fits one specific use-case, and at the high-end (AAA) you really can afford to build/maintain something competitive. The middle-ground might be dangerous.
That being said, there are literally dozens of abandoned game engines out there from solo "game devs" who never actually got around to making the game.
Is there? I can't think of any examples that come to mind. Most indie devs I know that roll their own engine have no regrets. I am curious who comes to mind that says otherwise publicly?