[DRW_]

They can really only remove the DRM on games that use Steam's own DRM, there are plenty of games on Steam that use third party DRM that they couldn't really do much about.

However, on the flip side, there are also a good amount of games on Steam that are totally DRM free and Valve wouldn't have to do anything for those games in the event they shut down.

[grogenaut]

I believe they've stated in multiple places that they have budgeted for running the auth and entitlement systems. They set aside money in escrow to do that. Those systems are cheap compared to the CDN (which is also getting much cheaper). A small team could have a multi-year runway for running auth and entitlement.