yes, but then they would have upset local admins for bypassing the local resolver. that is still an issue with httpdns, but now they have a better argument against using the local resolver as default.
the ideal situation would actually be to implement httpdns on the OS/router level and allow the user/local admin choose the policy. i expect that this is going to happen soon in most linux distributions.
Surely they could just as easily report all DNS queries to Google under the guise of telemetry or search optimization or whatever. And of course let people disable that, which about 0.001% would do.
Httpdns is too complex of a solution to the business goal you’re suggesting. There are much simpler / less expensive ways of doing it.