Synth nerds got it right: open specs, and a general industry-wide desire to make things play well together. After all, its music, this is why music works in the first place..
Totally, and I think the need for MIDI Guide - the fact that MIDI CC/NRPN is pretty much a free-for-all - is also why the spec has such staying power. It's so unopinionated that it imposes essentially zero constraints beyond message size. I love it.
