This just shows that the barrier of entry of a new phone OS is more than $0. You can pay app developers to port their apps off of play services, you can pay developers to add support for your attestation keys. Considering how many billions of dollars Android makes for Google, there is a room for a return on investment for an alternate OS to enable investments into a new OS.

How much do you want to pay? Who will be paying? Big companies will probably laugh such an effort out of the room, nay, they will not even let you into the room to talk with them.