It isn't all billionaires but they are part of the picture as it is probably around $55 million per seat for orbital flights though the exact numbers are not disclosed.
Axiom's last mission had two Saudi astronauts (Saudi airforce captain and a biomedical scientist) funded by their government.
The next Axiom mission will be flying astronauts for the Turkish space agency(air force colonel), Italian defence force (test pilot) and Swedish space agency/ESA (test pilot, esa astronaut) as well as their Axiom commander who is a legendary ex-NASA astronaut.
Even the upcoming Polaris Dawn which is funded by billionaire Isaacman will have two SpaceX lead operations engineers and an ex-USAF fighter pilot onboard and Isaacman is a respectable pilot himself. They are going to be pushing private spaceflight to new limits.