> There's going to be a lot of resistance to distros shipping a binary they didn't build from source. It might work if you could ship Tow-Boot on the hardware and make it optional for the OS to care, but unless I've missed something OS integration is needed (if nothing else, because it has to share storage).

That's kind of the point here -- distros would stop shipping the bootloader, and the bootloader would be independently managed, to be treated as a board firmware instead of os package.