Businesses and organizations pay Tsoukalos, for example, to give lectures and presentations for profit at various events and seminars--meaning free travel expenses as well as the lecture fees. For many years Zecharia Sitchin ran "Sitchin Studies" seminars where believers would come from all over the world to take (i.e., pay for) "classes" from him to earn "Sitchin Studies Certificates" done up like fake diplomas. Needless to say, skeptics are not as in demand on the lecture circuit since they tend to prefer real diplomas.
Additionally, cable TV pays travel expenses for these so-called "scholars" to visit ancient sites to do on-camera bits for their various alternative archaeology shows. The theorists, in turn, use those jaunts to tourist attractions as grist for their next books, as "research." To be fair, skeptics can partake in this same perk, though the number of slots for skeptics on cable shows is far lower than the number of vacations provided for free to ancient astronaut theorists.