The "monoculture" has never been less of a threat. WPT.FYI is driving towards asymptotically perfect compatibility and behavior. And the real web, the long-tail of websites, is too chaotic to be controlled by any entity regardless of browser market share. Chrome can cook up whatever API they want, no website can be forced to adopt it. And if someone can't use some WebMIDI site on Safari, well, they can't complain, they didn't want that site to exist in the first place.

It's simply not a good excuse to defend the iOS browser ban.