Well, Valve does a bunch of experimental stuff like biofeedback testing and eye-tracking movement for FPS controls, etc. Much of which doesn't see the light of day for the consumer or their end products, but it's something they do for their knowledge and to see if they can implement it in their games. Some of that undoubtedly factors into the extremely long dev cycle for their games. And if you listen to the dev commentary on their games, they test and iterate over and over and over again. The amount of polish and tweaking on their games is ridiculous, but it all adds to a longer development time.
On top of that the group of people working on Steam are definitely not the same people that develop their games. It's a little silly to think that a designer is going to be the same person making the business deals and programming for the Steam platform.
Stardock, while a great PC developer (barring a few recent mishaps), had a lot of problems with Impulse, and they're nowhere near the size of Valve, nor do they have the same amount of capital. And Wardell has said some silly stuff in the past, plus he's almost exclusively focused on business, so I'm very inclined to take what he says with a large helping of salt.