yes but real world applications often need to support more than safari and chrome, so until they are supported across the majority of them including older versions still in wide use then its still a no go for the majority of use cases.

Mobile is all about Safari and Chrome in what concerns Request For Proposals and delivery acceptance testing.

So real world customers don't care about anything else. If it happens to work, or a team member decides to go at it on their own outside project budget, it is a nice to have feature that's it.

Yes, so my point was that the authors of UI frameworks perhaps don't care about mobile only.