Well, it's as you wrote: they are making the source available, albeit in a very inconvenient way, and because there is no time limit specified, they're complying with the letter of the GPL (although not with its spirit), so you can't even realistically sue them. And the number of people who buy new Pixels to immediately install GrapheneOS on them is (no offense) negligible, so I don't think they'll see a sales impact from it...
Which is not to say that I'm on Google's side, this is absolutely a dick move from them, and they wouldn't have done it 20 or even 10 years ago, but today's Google is definitely no longer the "don't be evil" company.
> so you can't even realistically sue them
Genuinely asking: are you a lawyer?
Sounds to me that going from "it works easily and rapidly" to this deserves a big big fine. That's the only thing they understand.
> they are making the source available
Not in the preferred form for modification expected by the build system and not in a reasonable amount of time. It's artificially delayed with no legitimate reason.
> And the number of people who buy new Pixels to immediately install GrapheneOS on them is (no offense) negligible
Nearly all of our current users bought a device specifically to install GrapheneOS. Our current userbase is around 500k and many of those are users had one or more earlier devices with GrapheneOS. Our userbase is rapidly growing. Look up how many Pixels are actually sold in a year. It's not negligible at all.
There are also many large companies wanting GrapheneOS devices with official support from the OEM.