Google's Android 16 changes could be like Red Hat locking out public RHEL sources (versus CentOS Stream sources), where Rocky Linux and AlmaLinux had more steps but weren't dead. Rocky Linux and AlmaLinux 10 came out even with the restrictions. After all, non-Pixel and EOL Pixel phones long had to build device trees.
Or it could be like the OnePlus 10-series all over again but with Pixels: a harder to flash device. The way OnePlus removed unrestricted recovery tools with the OP10, Google removed device trees. While the OnePlus 11 had custom ROMs, the 10, 12 and 13 series didn't. And the OP11 only got it because of a hardware exploit.
The best case scenario is the Red Hat scenario. But don't discount the OnePlus scenario: unlike RHEL Android isn't limited by the GPL. And even I know so many OnePlus-to-Pixel converts, just for the same thing to happen to Pixel.
Yes, Google didn't remove the Pixel 6-9 flashing tools for Android 16. Maybe we'll have a lifeline. Or maybe we need to lobby the EU and certain US states (assuming either will listen) to open up devices.