You forgot AMP and AMP for Gmail
I suppose that's me in the super-privacy-nerd bubble. Having moved to Fastmail for email and using Firefox for Mobile + Startpage search, I almost never encounter Amp in my own SERPs (not that there's much AMP content out there for Clonk Endeavor ;P).
Or let's look at it differently, if you are Google and find that a new, HTTP-incompatible protocol would make things better for a significant number of clients, how would you develop and push for that new standard in a way that people won't complain about anti-competitive behavior like you are complaining above? And are you sure that following those steps won't result in other people on HN complaining that it's anti-competitive?
IMHO, google would have been fine if they had done everything the same but instead of basing mobile search results on AMP usage, they had based it on page load time metrics.
EDIT: The issue with AMP is less that Google created a new standard and more the way that Google has tried to utilize its other properties to force adoption of that standard in ways that seem more focused on benefiting Google than the internet as a whole.