> The calculus is very very very boring and simple. Game devs will support every single platform on the planet in which the cost to support that platform - both directly and long-term maintenance - is less than the increased revenue that platform provides.

Companies end up not doing profitable things all the time, for many reasons. One rational reason is that while action 1 might be profitable, action 2 is even more profitable. So the fact that Linux is not supported does not show that it would not be profitable, but rather that there are other things the companies can use labour for which they think is even more profitable. If they could freely clone their employees (and "unclone" them afterwards) all profitable things would get done.

(This is just nitpicking about your economic argument, I have no reason to think your conclusion is wrong).