We were doing this decades ago with engineer's HP C3600s under their desks. It wasn't AI, just low-priority HPC / fluid stuff batched out to hundreds of workstations.
And on IRIX, SunOS, and DG-UX boxes too. Once Linux existed for a bit, they were added to the fold. The software to do this - Condor - is still maintained.
That was the original pitch for Ian Murdock's Progeny startup in the late 90s: a Linux-based distributed filesystem for corporate desktops to boot into overnight for distributed computing.