SNL doesn't use a person's popularity to make money. They might mock them in some skits, but that isn't the whole basis for the show.
Yes they do, why else would they have guest hosts? They sell advertisment time, the more popular the show, the more expencive theadvertising slots become.
Guest hosts give permission. We're not talking about guest hosts
Okay, well, what about Will Farrel playing as Robert Gulet? Or, as Hary Karey? He is using a person's populatiry to make money, the same way that Norm McDonald would pretend to be Burt Renolds. The reason why they make money is only based on the people they make fun of. If they made jokes like Joe does, no one would understand. ("Well, today jessie and I went to the mall and we saw lary, he is so dumb. Tehehe") They need popular people to make fun of, so the show can sell advertising time.