I think I'm an anomaly. No, I know I'm an anomaly but that's another story
I don't know anyone that has an ATP that hasn't at some point in their lives made a significant portion of their income from flying. No one I've asked knows anyone either.
I got my multi-engine ATP a little over a year ago, already had CFI, CFII & MEI. The most I've made flying in a year was well under 1% of my income. For the last few years I've charged "make a donation to the Flying Samaritans, Tucson Chapter for what you feel the instruction was worth" so zero dollars have come to me from flying "professionally" for quite a while.
How many people do you know that have gone up through all (well, most of) the certificates and ratings on their own dime just because it was a challenge and made them a better pilot ?
Just curious . . .