UFC's history shows otherwise, though. GSP had a strong fan base before MMA was really popular. He's a big reason why fighting became sanctioned, and then big, in Canada. Same for Conor & Penn. Brock had his WWE fans. Ronda was a media darling.
Then a tier below you have Anderson, who only really became popular late in his UFC run. Chuck was thought to be boring before his rivalries with mainly Tito and a more friendly trilogy with Randy. Jones who had a bunch of stuff that made him a 300k-close to a mil draw, also depending on the opponent. Rampage for knocking out Chuck in the rematch for US popularity.
Lee's better than his record shows, and will be a mainstay top 5 fighter, but him being the next Conor was forced and he'll have to go on a serious run to get into that 2nd tier, while 1st tier would've already happened.