Clearly, Google wants to be able to support companies which want to sell locked-down phones.

But as long as they sell their own phones with unlockable bootloaders, you can vote with your wallet and buy those phones.

I am concerned about the reduction in use of the GPL, but what I care about is being able to run and modify the software on my phone, and as long as Google is still releasing AOSP (and the Fuchsia open source project), and selling phones that are unlocked, I'm happy enough with that.

Yes, they might change their policy in the future. But for now there's no indication that they intend to do that; they've always been good at selling their own phones and Pixelbooks with unlockable bootloaders that does allow you to replace the ROM if you want.