The SensorVault data is “just” the Google Maps Timeline data though, right? Which people have always been able to turn on and off, if they knew about it.

I feel like Google not really respecting a concept of user consent and pretending people agree to poorly-publicized and often-modified tracking programs is a different, and, frankly, weirder, privacy problem than there being closed source stuff running with high permissions. If you could revoke permissions from Play Services, or if it was source available or even free software, that wouldn’t solve the problem because it would still be able to do stuff Google had manufactured consent for it to do.