Emerson and Wilson's father was a journalist, which to me, is middle-class. So to the best of my knowledge, no money there. Somewhere along the line Emerson obtained a farm on which he grew oranges. I believe it was or is a very large farm (might be a better word than "farm." "Plantation?") When he won one of his Indy 500s and was in victory circle, he gently pushed away the offered jar of milk to drink some of his own orange juice. I'm sure he has other business interests as well.
Wilson "ran" the Copersucar F1 team, and while I believe that he was in charge of the whole thing, I don't know his exact role. I'm quite certain that he was at or near the top. And that
Copersucar paid a healthy sum to get the team up and running. Despite the lack of success, I can imagine - without knowing for sure - that Wilson paid himself at least decently and probably his brother as well.
After Jody Scheckter retired he developed a firearms training system to train police forces. Instead of using bullets, it used light, or laser light. Something like that. It's my understanding that he made some good money from that. A few years ago I saw, possibly on YouTube, an interview and at that time he had a farm in England where he raised cattle organically. I suppose that is worth his time or he wouldn't be doing it.
According to an article in a Watkins Glen race program, Howden Ganley was part owner of a tool-making business and owned a couple of F1 cars already. I expect this might have been '73 or '74. Granted, this is before he retired...
Ganley and Schenken had the Tiga racing car manufacturing business, and I've no idea how that turned out for them. I'm sure it at least paid the rent and who knows, they might have had some cash leftover afterwards.
I have also read that Eddie Irvine has real estate. Lots and lots of real estate, and much of it was the kind of houses that we might see on "Lifestyles of the Rich and Famous."
In the documentary "Racing Stewart," JYS said that when he retired, he expected that he would have about 5 years that he could continue to make money based on his name and fame. Funny how that turned out!
Interesting thread. I wonder about such things, too.