Well, there is also the contention ratio to consider. All internet connections are shared at some point, thats the entire point of the net. So what happens is you get an ISP with a 10Mbit line. (this is a budget ISP ok?) and then they sell 1Mbit lines to 200 customers. The theory being that for "normal" use people don't max out their internet connection 24/7. So, while customer A is downloading a webpage customer B is reading a page and his connection is idle.
Of course, bottom line is as well as your internet connection also relies on the connection at the other end. No good having a 100Gbit internet connection yourself if the server you are downloading from only has 512kbit.
