The same was true when IE dominated. The point being missed is if a single browser is allowed to dominate across the board, the owners of the technology become the gatekeepers of web technologies. That would have been extremely bad under Microsoft, and it is going that way with Google. In fact, there was a groundswell of negativity towards WebKit until Google broke the hegemony with by forking it, creating Blink. Which is now in a significantly more dominant position than WebKit ever was.

I’m not suggesting that Apple would be any better or that not allowing other browser engines is a good thing. However, the fact that they don’t is keeping Google/Chrome/Blink from having total dominance of the web.

I'm a regular desktop Safari user and you'd be surprised how many websites are just flat out broken in Safari, especially government sites. Part of the reason I use it as my daily driver is to ensure that the websites I'm working on get tested properly in Safari since the defacto browser for most developers seems to be Chrome.

The main reason safari is used in desktop is because other browsers are not first class citizens. They have access to resources that third parties don't.