They absolutely do not support the architectures in the same way. Most NetBSD ports are cross compiled and not tested, you are lucky if they boot before hard locking.
OpenBSD has a strict policy that supported architectures must be self hosted, tested, and built against HEAD constantly.
There's also bitrig, a fork of OpenBSD on not so friendly terms. OpenBSD lost a number of developers when that happened. They don't appear to currently support 88K, and aim to target current architectures, but I wouldn't be surprised if it'd be worth their while to support another architecture to accommodate a developer who would do all the work to maintain that platform, as well as contribute in other areas.
I believe that the Foundation does not have a lot of hardware, volunteers own and support them. As of a few years back there is a "tier" system for NetBSD support too, http://www.netbsd.org/ports/#tiers which means that it is up to eg the Vax maintainers to keep things working rather than everyone.
If the answer is "NetBSD", let's consider that the expenses in 2012 for the NetBSD foundation were $6k [0].
Either they don't support the architectures the same way or they are spending the money in a smarter way.
[0] http://www.netbsd.org/foundation/reports/financial/2012.html