Then Alphabet will come up with a new bullshit idea, “remove the limits for ‘trusted’ advertisers” so that they can inject more code than allowed as long as they keep paying for their ad “partnership”
It became difficult as Web technologies grown complexier, such as implementing native CPU instructions through WASM, bluetooth through Web Bluetooth, 3D graphics through WebGL, NFC, motion sensors, serial ports, and so on. Nowadays, it’s simply too hard to maintain a browser engine, because many of the former alternatives were abandoned and became deprecated.
I dare anyone to even just compile a document containing all the standards you’d need to implement