> Granted, my experience is from 15+ years ago, but I remember wanting to play an MP3 on my new Linux desktop. Most articles explained, with a straight face, that I "just" needed to re-compile my OS to get audio output.

Honestly, unless you're talking about the early 1990s, this should never have been your experience. Ever.

> It would need to have a dominant desktop distribution -- 60%+ market share of Linux installs

Ubuntu.

> It would need to eliminate 80% of the choices. It would need to handle 99% of desktop use cases with zero configuration.

A driving philosophy of GNOME, which Ubuntu uses by default.

> And finally, any configuration that is needed would need to be simple settings that can be configured via a GUI, with configuration via shell there only for those who want it.

Difficult to tell what's fully meant here, but since both Mac and Windows fail spectacularly at this requirement too, I imagine it's probably not actually that big of a deal.