Earlier quoted context omitted.
> I can trust that anything I purchase from Steam will be around for a long time. Unless the publisher pulls it or pushes an update cutting music because of license deals expiring. Or gets a stealthy replacement with a worse remaster. Or your OS drops 32 bit / x86 support.
I agree with most of your comment ... but "OS drops 32 bit / x86 support" gets a hard disagree. Steam provides the game . It "will be around for a long time." It is not Steams job to ensure the game runs on every device or OS version for eternity however. That is up to the publisher of the game. If you install Steam on an older version of the OS that does have 32bit/x86 support, Steam does its job. I do think however…
So even if your game is 64-bit, you still need 32-bit libraries and OS support to run the DRM. Sucks when either your OS doesn't support 32 bit (MacOS, OpenBSD), you don't want to add 32 bit multilib, or you're doing funky emulation on a non-x86 machine where you can only effectively emulate x86_64 (see: ppc64le).
These are all niche situations (the last one almost facetiously so), but the point stands. I really wish valve would release a 64 bit client on Windows and Linux :/