Keep in mind that OpenBSD is by the developers for the developers. That it's also useful for a lot of users is just a nice side effect, helpful for testing and funding.
At home when things get though, we cut costs and hope for better times.
If OpenBSD isn't exaggerating about shutting down the project, then it seems reasonable to review their policy regarding old platforms and focus on what gives the most return.
Sounds like people should donate then yes? Shut down a niche arch and the developer will leave and not contribute anything, even to x86_64, just the same as the project going broke.
Keep in mind that OpenBSD is by the developers for the developers. That it's also useful for a lot of users is just a nice side effect, helpful for testing and funding.