I agree that private companies can be good and I use Steam a lot, but Valve sucks in other ways. Their community is awful and developers can have posts openly calling for their death or calling them racial slurs and Valve support will tell them they won't remove the posts. I don't mean they deny the support request, I mean a person will respond and say "Yeah manage your community better." This is despite the fact they give no tools for community management.

But being a public company wouldn't make it any better.