Exactly. Apple can choose to implement what they consider to be a safe interface for WebMIDI. Instead, they refuse all of it?

In my opinion, Apple has an incentive to keep the web crippled in some aspects, and this is just another symptom of that deeper underlying cause.

Well, I guess if I ever need WebMIDI features, I'll put a banner for Safari users to switch to Firefox.

(Or.. Maybe Firefox on iOS is forced to use the same engine as Safari..?)