I think what Valve gets right is how much value and respect it provides to both players and developers. Of course you can find some issues here and there. But in general, neither players nor developers are angry or frustrated with Valve/Steam.

It's no surprise that it's hard to compete with that.

On the other hand, I find it surprising that no one thinks there is a way to take operating system market share away from Microsoft with a better end user operating system. There is constantly new annoying stuff practically forced upon you and people are complaining left and right. Of course Microsoft has built several moats, but this level of disrespect against your own users has to backfire some day.