That's more or less how HTML has always been. Before Chrome, it was IE just adding stuff. Before IE, it was Netscape just adding stuff. JavaScript itself is just a browser adding stuff.
Like it or not, W3C standards have always been reactive to what browsers are already doing.
And what's really remarkable about this list is that quite a few are supported on Safari on Mac, just not on iOS. Like autofocus. It's just a simple attribute you can put on an <input> tag that autofocuses that element when the page loads. It's on Mac Safari. It's on Android browsers. It's just not on any iOS browser because, you have to assume, someone at Apple held it back for not very good reasons.