So you're not going to get it until your OS decides to, and if its implementation is poor you're SOL?
Not at all. If you want or need a feature it's not some "my browser has to support it or my OS does" dichotomy.
As a couple parents up stated, there's no technical reason a browser has to have a transformer embedded into it. There might be a business reason like "we made a dumb choice and don't have the manpower to fix it", but I doubt this is something they will accept, at least with a mission statement like they have.
I much prefer every individual piece of software and website I interact with implement their own proprietary AI features that compete for my attention and interfer with each other.
Choose the implementation that you like, or contribute to help make one better. Just like all other software on your computer.
Don't like Libreoffice's implementation of Word support? Install Koffice. I take it you've never installed non-OEM software on your computer?