It's very important to be precise. Depending what country you're in, there could be full professors, assistant professors, associate professors, instructors, and other positions. Some of those positions might be well paid, but it's a safe bet that some of the others are not. So if you're looking at one full professor's salary and thinking that most other people with the word professor in their name make the same salary, depending what country you live in, you would be mistaken.
Actually wait a second, that's true in every country.