Who still uses an 88K machine? I have the CPU board from a DG/UX machine, but the latest chips are from 93/94.
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.
It is until the developers can't afford to keep the lights on.
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.