Sounds like a group of bad developers that want to not develop for standards supported by Safari and Firefox, instead they only want to develop for Chrome and Chrome “standards” like they did for IE6. Couldn’t possibly have multiple browser engines to have to test your code on.
Having to support Chrome(ium), Firefox and Safari is an absolute picnic relative to the bad old days of IE6 and earlier - especially considering how much more complex web pages/apps are today (and the extra challenge of supporting desktop/laptops, touchscreen tablets
and tiny mobile screens). That said, Safari - especially mobile Safari - is lacking on some features, esp. more bleeding-edge ones, and it *is* rapidly becoming the more troublesome of the three to support. It's nothing like the royal pain that was IE6, though.
L
ook at the usage stats: (That may not be the best stats site, but it's hardly making extraordinary claims) Across all platforms, Chrome is dominant, Safari is a poor second, but still significant and the rest are minnows (esp. as most of them apart from Firefox are either Chromium or Webkit under the hood). I wouldn't bet against Edge in the future, but again, that's basically Chromium, so it comes down to whether you want MS or Google to harvest your data.
Tablets - (where no one really competes with iPad) are a bit different - mostly split between Chrome & Safari, with "Android" (i.e. Chromium) a distant third, and nothing else worth mentioning.
In either case, the effect of allowing competition with Safari on iOS will simply be to hand even more domination to Chrome, which is what punters are choosing in droves on the platforms that
do offer a choice.
Also, I suspect some of Safari's deficiencies are "strategic" choices by Apple to limit the power of webapps - allowing Chromium browsers (and, maybe, Electron apps) could be a disincentive for developers to write "proper" native Apps - especially in the case of the iPad: part of iPad's advantage over cheap Android tablets is the availability of native Apps optimised for tablet use.