And if enough developers simply ignored Safari then maybe it would force Apple to either simply adhere to web standards or allow competing browser engines... Catering to them signals that their shitty behaviour is condoned.
This is the kind of thing that only web devs care about. If someone can't use your web app on their phone, they're going to never try your app again, not demand changes to the browser.
It's generally the first thing we check for when trialling new software. Does it work in Chrome/FF/Safari and on iOS/Android. If not then we won't continue the trial.