I'm not sure how big of a gamble that is. If he gets Starship into orbit he can start getting serious revenue from Starlink. Then he needs to transfer fuel in orbit to send cargo to the moon and mars. At that point he can send people and the return trip after two years will basically be free because some Starships will be returning to Earth anyway. I'm pretty sure he can get enough guinea pigs to commit to a 2-year trip. Then you iterate on the next batch of guinea pigs. Maybe he sends retirees who don't have that much life expectancy anyways.