When you say "supported the defacto standard", I suppose you mean "Apple just did something, and the others copied it to be compatible". The problem is, as it

When you say "supported the defacto standard", I suppose you mean "Apple just did something, and the others copied it to be compatible". The problem is, as it always is, that since the details aren't specified the implementations turn out incompatible. A concrete example: Should the touchmove event trigger the mousemove event? I believe it does in IE and Firefox, while it does not in Chrome and Safari. It isn't specified anywhere, and can make it incredibly complex to implement something that works with both mouse and touch input. And it is exactly the type of thing that Pointer Events sets out to fix. This is also exactly the same story as with the <meta name="viewport"> tag. Apple did something, and the others made not-fully compatible copies. No exaggeration: Right now the only(!) thing that works consistently cross platform is setting width=device-width. It is insane, and it hurts the web.