I'd say that another big factor is the financial part. Take your average game studio, even large-ish ones always have a very uncertain future after their next g

I'd say that another big factor is the financial part. Take your average game studio, even large-ish ones always have a very uncertain future after their next game. When your ability to make payroll depends on getting your game out at the deadline agreed with/imposed by the publisher, this is going to mean plenty of crunch time. And then you may get laid off once the game is out, because the studio doesn't need a lot of programmers during the pre-production phase of their next game.