Perhaps not, but if it didn't it would be because the rest of the org that didn't want to do Steam would have been more empowered to stand up to Gabe, whereas with Valve's flat org, Gabe is God and everyone has to do what he says.

It's probably best for Valve that Steam did happen, but if it's due to Valve's flatness, I would attribute that to the org's inability to resist Gabe rather than any sort of bonus wisdom that arose from that flatness.