You can run steam in big picture mode, and there are ways to add links to games from other game stores to steam such as https://github.com/PhilipK/BoilR

It's not automatic or perfect but it does work.

I'm aware, but that is indeed a great thing Steam offers. I think it's janky enough that if there's one way to out-steam Steam it might be making the broader PC gaming universe as plug-and-play into a console experience as possible.