Many times the network engineer is the referee between the users wanting more bandwidth and management wanting to put more people on the network. These issues may be political or real. A practical number of users on any one LAN segment depends a lot on the applications being used as well as the number of devices, distance constraints, traffic volume, and so on.
Any way you look at it, networking is all about taking turns. Obviously, the more people you have to take turns, the more chaotic things can get.
Hubs and repeaters really don't do a lot to assist with nodes taking turns; they are first rate for extending networks or collision domains, however. Other devices facilitate segmentation to assist with such constraints as ...