Leveraged their monopoly ?
How does that work exactly for Windows, MacOS and iOS in your mind ?
All of which they will use to yell at you to switch to Chrome, and will sometimes cause to actually be faster or more featureful when using Chrome rather than any other browser.
It's a pretty clear case of using your monopoly in one market to artificially prop up your entry into a different market, which is very much the sort of thing that has traditionally been frowned upon both legally and morally.
If anything, it is impressive how Chrome has managed to be the majority browser, given that by default we get Edge on Windows, Safari on MacOS/iOS and Firefox on Ubuntu.
So when one browser maker wants a new feature they make a spec and implement it. If it seems to be useful other browser makers will implement it, maybe with changes they think improve it. Then the standards bodies will look at all those and make a standard.
For that particular feature it was actually first suggested by people from Intel and Apple. Google thinks it is a good idea and is the first to write a spec for it and implement it. It seems highly likely that Mozilla and Apple will follow and it will be standardized.