This a major leap forward in human innovation and engineering. IMO, this could be as influential as the adoption of electricity/setting up of the power grid.
Because there is a ton of hyper fixation and rash decisions being made over something that puts words together. It seems very unwise to add a new browser API for something that is in its infancy and being developed.
For instance I don't need my browser to pass the Turing test. I might need better filtering and better search, but it also doesn't need to be baked in the browser.
Your analogy to electricity is interesting: do you feel the need to add electricity to your bed, dining table, chairs, shelves, bathroom shower, nose clip etc.
We kept electric and non electric things somewhat separate, even as each tool and appliance can work together (e.g. my table has a power strip clipped to it, but both are completely separate things)
triggers the part of you that says "this tastes good" but will rot your teeth
In particular I get to choose the best options for each of them (in particular search, filtering and security being independent from each other seems like a core requirement to me). The most telling part to me is how extensions come and go, and we move on from one to the other. The same kind of rollover won't be an option with everything in Apple's AI for instance.
This could come down the divide between the Unix philosophy of a constellation of specialized tools working together or a huge monolith responsible for everything.
I don't see the latter as a viable approach at scale.