But is every feature in a browser supposed to be standardized? Like, it's against the rules somehow to develop features without asking permission from Apple and Mozilla?
It's not against the rules, but it is hostile to the web. Forking the web because a company is big enough to do so may sound just dandy to you, but to the rest of us who have spent decades working on interoperability it's a big middle finger.
Apple doesn’t have a veto. If two independent implementations are required for something to become a web standard, all Google have to do is convince anybody outside of Google to implement their specs, such as Mozilla – who Google pay billions of dollars to.
The problem with all of these new specifications is that Google can’t convince anybody to do this, no matter how much money they throw at them. That’s not an Apple veto stopping these things from becoming standards, that’s Google pushing shitty specs.