Anyone in charge of a non-publicly traded company will want to do what’s best for the company in the long term instead of milking as much from it as fast as they can, so I don’t think that replacing Gabe by someone else will be the end of Valve like so many people claim.
The problem is that you can never be certain about someone’s ability to stand their morals atop money until it is truly offered to them. Supposedly Gaben has turned down Billion dollar offers for steam. It is certainly not every person who will do so and it is hard to know how a person will react until that is truly offered to them. I don’t know that I’d turn it down (though I also don’t know how much Gaben makes).