The terms "legend" and "HoFer" are thrown around so much here and by the UFC they have lost all meaning.
"HoF" fighters IMO are long term champs like Aldo, Jones, GSP, Anderson, Fedor, Chuck, Faber, Hughes, Tito, Royce, Franklin, etc.
"Legend" is hard to define in a sport so young but the closest are people who went on monster runs against great opposition where they looked unbeatable, like Anderson, GSP, Jones and Fedor.
I don't consider Stephan Bonnar a "HoF" fighter because he helped expand the brand. The only people who should care about the financials of the UFC are the UFC and their business partners, trying to define greatness by profit to the UFC is retarded. In that case PVZ is probably "greater" than Machida.