This wouldn't work with Apple products because Apple ultimately has control over the hardware. You don't want a server that suddenly shows "Please enter your AppleID" in the middle of something, for example.
Sun Microsystems were also big in universities. As were IBM. Lots of people believed the "servers have special hardware" voodoo back then, and parroted that it's bad news to run servers on consumer hardware.
Somehow, decades later, the meme refuses to die. Unlike Sun Microsystems. Or IBM's Unix server business.
If Google had used Apple appliances for their servers they would be violating the EULA and have lawyers knocking on their door.
Apple appliances are made for consumers. Apple's lawyers were not paid to cover business usecases, so they basically don't allow it.
The point is: commodity hardware is powerful, and it's interesting to explore its capabilities outside of its original purpose. Apple or not.