Buying a pixel is more money for google. And buying Shiftphone or NovaCustom is more money to develop alternatives. Only GrapheneOS monopoly in alternative space is not desirable.
NovaCustom is great company who don’t go on an easy path, but works to advance privacy and security (their previous product also took many years to advance it to this stage: Finally! True Privacy in a Laptop: NovaCustom Review - Techlore.TV ).
Shiftphone and iodeOS may not be perfect, but a right step. They plan to invest in iodeOS development like they do (example NovaCustom contributes 10 000 USD to Heads firmware - NovaCustom ), and shiftphone also great to support alternative phone makers.