They all do. You can argue it's too high but the issue is that they all own those platforms and the hardware you develop on (except Google). Valve, not so much.
>The difference is people actually like using Steam. They actually want to be locked in.
yup, and that's where the danger starts. People like being locked into Apple as well. the consoles all conditioned people to being locked in. I understand it, but don't think it's a good thing.
Microsoft does technically have a lock in with PC, but they have enough historical lawsuits on those issues that they are lax on what is hosted on Windows. The reckoning for Apple/Google is definately coming, though.