anothername: Currently they claim all their newer; up to a certain point, rely too much on steam to be released on gog. So they can only work on steam.
Apparently they save more by not developing the stuff steam does for them than they would gain by an independent piece of software.
Actually, I'm not sure that the use of Steamworks is such a restriction. FIrst because that would be a hell of an anticompetitive practice, second because what Steamworks delivers is Tools for sales and use tracking, an anti-paracy suite, a support layer for microtransactions, and for regional locks, an achievements system, and Tools for update deliveries. The Clausewitz engine remains Paradox's , and anon steam version ought to remain possible by disabling the Steamworks functions. Nw, Paradox does not want to have 2 parallel versions of their current milkcows, that's for sure, but just like cows, once they will have delivered enough , selling their meat here is a way to generate additional profits