The Devs take a pay for timed exclusivity and this helps development.
This is only in the case of Indie Devs. And again, only if the deal is struck before the game is done. For any studio tied to a publisher, it’s just money up front for the publisher.
Plus, I remember the stories some Devs told of how egs tried to strong-arm them into going exclusive. Didn’t score them any bonus points in my book.
But as I said, everyone has they’re own principles.