- Google has majority share of browsers with Chrome
- Chrome has QUIC enabled by default (opt out via chrome://flags)
- Google has a large amount of resourcing allocated to Chrome/Chromium. They ultimately control whether or not code is accepted
- Google also owns DoubleClick; ads are already being pushed using QUIC
- Regular end users are likely not aware of QUIC. Sure, a more advanced user can show it in the dev tools if you enable it and then look for it. But the problem is more that people aren't aware this is something to look for and they are opted into this
Showing a banner and trying to sell a product is one thing. But using a protocol that the user is not explicitly approving of to track / advertise is another thing. It seems to me (and maybe I'm wrong) that they are using their borderline-monopoly position in the browser market to opt people into questionable advertising technology