Granted - the hardware is open so it doesn’t have to be the original manufacturer coming up with new CPU modules.

This substitute manufacturer has to be financially motivated to do so, i.e. there should be enough potential customers

It's interesting you say that, since that's one of the major benefits of open hardware - you're not beholden to the survival of a corporation to continue having support for your tech. Anyone can come along and get a PCB produced by one of the many "print on demand" services. Someone with similar skills to the team at MNT can pick up the entire ecosystem and build entirely new hardware for it without a shred of friction or red tape (or threat of lawyers lol) ... pretty badass if you ask me. Worst case scenario you hire/crowdsource someone to build an updated CPU module.