First of all, I am not here to insult you. But sometimes I make people very mad. You are very observant and intelligent. Perhaps that is way you have chosen not to dig into network documentation.
You assumption in you question does not ...
even quality as a wrong answer.Because a
wrong answerr becomes right when you just change a few words. I can't do that with your hypothesis.
The whole idea of TC/IP and others forms of packet communication allow for many users to share the same network, even when the network seems to be a chaos. Sharing is done by need and priority and other factors to give the best possible speed to active users.
Aside from hardware issues, the convoluted network you describe can give full speed, over 95%, to a single user while the other computers are idle.
Here is a better definition that what I can give:
http://en.wikipedia.org/wiki/Packet_switchingYou may also want to read:
http://networksmadesimple.net/
