Because the definitions that exist are wrong
Speed vs. Bandwidth Explained – Arvig
Bandwidth is a term that is used a lot in the computer and networking world. In fact, it is used so often that it is easy to forget that some people do not really understand what it means.
A quick Google search for “what is bandwidth” yields two different dictionary definitions, neither of which are correct. This article explains what bandwidth is, how it is measured, and how much you need for different tasks.
Bandwidth is defined as the maximum amount of data that can be sent over a specific connection in a specific period of time.
