Chrome likes to make up new "standards" and then some websites adopt them immediately.

That said, I can only remember two instances of that slightly inconveniencing me in the past, and both times I was inconvenienced by a Google-run website: once upon a time Google Earth refused to work, and once upon a time I couldn't tweak my Google Meet background. Both are no longer the case.

Citation needed. I've seen the opposite--unless there's a very specific niche that can't be otherwise solved, there's huge internal resistance to going it alone.

The biggest counterexample I can think of: WebUSB was critical to Chromebooks supporting external devices, but I can see why Safari might not want it. It has Firefox support at last, though.