Earlier quoted context omitted.
I don't really understand this. You plan to single handedly replace the entire OS and security teams to maintain the OS on your phone for a decade? How will you update the kernel when the proprietary driver blobs stop being maintained?
Perhaps the more generous take is that, with FLOSS software, you don't have to go it alone. My Pinephone Pro will not be running security fixes I write myself. But entirely because of its open nature, it doesn't need to - it will continue to recieve updates for years and years. For once, the hardware of a cell phone is likely to die before the software.
The caveat is that sometimes an initiative can be funded by charity or bounty to keep interest, but relying on generosity for 99.99% of projects is a fool's errand.