I'm not going to buy Pixel feeding Google further with my pennies just to use GrafeneOS.
Maybe you should buy good devices from any vendor, and the market will do what economists say it should do, and keep making those devices. (As if!)
But Google is one of the rare Android smartphones vendors that allows you to install a custom operating system, while still allowing the same security as with the default one (ie allowing bootloader re-locking with a custom key)
Well you can always buy second hand/refurbished.