'Many' is relative. The reality is that there aren't many Wildlife Photographers, so even if 'many' of that niche group use $13K lenses, it's very, very few in absolute terms. However, there are probably a reasonably large number of photographers who shoot wildlife, and very very few of them have $13K lenses.
In the context of all photographers (with a DSLR or mirrorless body), few will own a super-tele lens. If we narrow that down to wedding and events photographers, I can't imagine any of them will have a $13,000 super-tele. But if we look at sports shooters and wildlife photographers, I expect and often see many of them with a $13,000 super-tele. This isn't to say you don't have the weekend adventurer using a 200-500 f/5.6 on a Nikon D500 and getting great results for under $3000. It is saying that many wildlife photographers will have one or more of these big lenses as it is a tool of their trade as much as the f/2.8 trinity is all but expected to be in every wedding and events shooter (even if we have some outliners that use a 35+85 prime combo or any number of other variations).
And of course 'many' is relative, it is not absolute. And I don't have the data to say that there are 1 million wildlife photographers and 100,000 of those have one or more super-tele lenses and that constitutes as many. What I have is knowing and meeting up on occasion with other wildlife photographers and they'll have a 200-400 and or 600mm f/4.0 with them and when I go to a national park or someplace more exotic or if I look at the equipment the BBC are sending a documentary crew out with, they are going out with a big expensive lens or two. The same as if you look at the Olympics and see the wall of great whites, you can conclude that many sports shooters are using these lenses because there isn't anything else and you just can't get close enough to use your 70-200 f/2.8.