This isn't even something you should be doing for your devs just because being nice to them is nice.
So many indies on their second and third games are showing that once you get the ball rolling on institutional knowledge (skills and tools developed during the making of a game, contributing to the next) you can SERIOUSLY up your game. And for a lot less cost than it would have been to go that big from the start.
Meanwhile big studios are dumping staff and therefore expertise like it's no big deal. Switching to a revolving door of subcontractors who can't possibly get to intimately know the games they work on.