Rather than rent it out (maybe some people would pay a few bucks a year for novelty web/mail hosting, but it's both too much and too little for most use cases, running the program of renting it probably eats up a lot of the revenue), maybe they could give compute time to universities for free, with the requirement that they provide some sort of display for museum visitors? There's probably some people with Monte Carlo simulations that could benefit from a lot of cores (if they get the M4 upgrade) while being on a student budget of $0. And if no one has requested it, they could run some BOINC project that has a nice visualization.

I doubt distributed compute in a bunch of old i7s is worth much once you factor in the electricity cost

The RAM shortage is bad, but not that bad (yet).