I compiled a "short" list of why amd how Safari is crippled. Not entirely on topic for the post, but seems appropriate as a reply on this particular comment ;)
This article is quite literally the only one that actually discusses actual Safari problems.
And even this article falls prey to "failures in web platform tests" which are a very poor indicator. E.g. Safari passing all accessibility tests is much more important than Safari failing most accelerometer tests that only Chrome passes (because this is Chrome-only API).
The WPT graph shows failures for tests that fail in only one browser. So the accelerometer tests, for example, would need to pass in both Blink and Gecko for it to count as a failure on Safari's part.
And even this article falls prey to "failures in web platform tests" which are a very poor indicator. E.g. Safari passing all accessibility tests is much more important than Safari failing most accelerometer tests that only Chrome passes (because this is Chrome-only API).