That was fine as long as the network was thinnet or thicknet as most universities probably were, because a well planned network would start at the hub and extend out and terminate. When networks became more based on 10baseT and you could add devices by just plugging a very cheap hub into a wall socket, and then plug another hub into that, for cheap, you could get loops more easily, and degraded broadcast quality, and that kills the entire network.

MIT originally was single /8 network (Class A from before CIDR), however they had it subdivided with routers AFAIK pretty soon.

CISCO had a lot of early customers among universities because dedicated box ran better than random unix workstation pulled out from other duties (or even sharing them) running RIP and the like.