What about the small matter of having to purchase a Google phone in the first place?
Given that there exist vendors like Fairphone/Murena that sell lower-performant hardware at much lower price points, it seems to me that the expensive but decent hardware (like Google's flagship) might be priced appropriately as well
Other competitors (that do track you, like Samsung) have similar price points for their high-end hardware and are again much cheaper for slower hardware. If selling data is so essential, they wouldn't allow removing the tracking. (Samsung may be a bad example because they removed it last summer, but root popularity has been diminishing since early android days anyway so I can't imagine it's a big factor for them)
The problem is not GrapheneOS, but rather that phone manufacturers other than Google don't care. Now if there were millions of GrapheneOS users, it would start becoming interesting for other phone manufacturers to care.
My point being that I buy Pixel in order to give more weight to GrapheneOS, in the hope that other manufacturers will eventually realise that.
E.g. a new Pixel 9a is currently 369 Euro in The Netherlands and 367 Euro in Germany. The Pixel 10a will be released soon, but the 9a will run GrapheneOS just fine (same SoC except modem as the vanilla 9).