Comment by zeroq
A guy who worked on Bioshock (lead design?) said in an interview:
"At work if we want to experiment with a new idea I have to assembly a team, and spend at least a month before we have something we can work with. Meanwhile, at home, I can make a whole Doom campaign in one evening."
(quoting from memory, sorry)
There are new games that still use (modern forks of) the Doom engine!
https://store.steampowered.com/curator/42392172-GZDoom-Games...