The prime reason for the Xserve line was to have a Mac Server that could go into schools' server closet to help manage all of the Macs in a school. It got sold

The prime reason for the Xserve line was to have a Mac Server that could go into schools' server closet to help manage all of the Macs in a school. It got sold in lots of other places for various things (e.g. that supercomputer at the time), but that was the overwhelming reason at Apple. The whole project long the things that got done on it were things that schools needed. There are a lot of schools, but once you have one in each (that had a large Mac presence), there was not a lot of growth room. I was working at the University of Wisconsin (Madison) at the time, and we had a grand total of 6 in our data center (yes there were more on campus, but in ones and twos in departments), and no big reasons to have more. And as much as I love working on MacOS, it (like Windows) is not well setup for use as a non-interactive node (e.g.: server or data processor node): the GUI gets too much priority, the filesystem is really slow to sync, and there are unexpected edges in setup.