He gets paid in credit card referral fees (affiliate fees) for promoting this lifestyle on his blog.
> why?
Because he wants to and it works
But the interesting question to me is
> why don't we?
Probably because it is insanely unreasonable for many to go through all the hassle for a few flights. I don't spend too much on flying but even twice the price wouldn't bring me to churn credit cards, save all the credentials, watch out for rewards, etc. This is all stuff I'd love to pay someone if I had to do it.