Also, personally I care less and less. As long as my banks and government apps work, I'll just not use somebody's service if they put up barriers like this.
If most people care less and less, the result would be that banks and government apps will also work less and less.
Look, companies have to prioritise. And the obvious way to prioritise is to say "users are requesting X A LOT and nobody requests Y, so we will do X". Companies never, EVER say "it would be more ethical to do Y, let's do Y".
As people, we can do two things:
* Push our governments to regulate that shit. That means, complain a lot to the government.
* Be vocal to companies and complain when they don't support your system. If enough people do that, it will be prioritised.
The hardware attestation (which is used by strict Play Integrity) checks the signature on your OS. It is totally possible to allow signatures other than Google, but Play Integrity doesn't do that.
Companies could totally decide to use hardware attestation and accept systems signed not only by Google, but also other systems (like GrapheneOS). But they don't care because not enough users complain to them.
Users of alternative Androids typically silently move to another service or stop using it entirely. Which is understandable but doesn't help the cause.