A quick flit around the wonder of the internet would seem to indicate a lot of people who have never been associated with F1 have done A OK.
http://www.celebritiesmoney.com/indy...ies-list-2015/
http://thenewdaily.com.au/sport/2015...d-sports-star/
http://tsmplay.com/money/nascar-drivers-salaries/
Net worths
Tom Kristenson $20M
Seb Loeb $55M
Tony Stewart $70M
Danica Patrick $30M
Jeff Gordon $150M
Kyle Busch $25M
So either try and get into F1 or go to America I guess.
Don't know what some of the Japanese drivers and some of the Asian championship drivers are paid???!
Webber is apparently on $2M a year at Porsche.
P.S. There are some contradictory figures around.
P.P.S. Wonder what some of the team owners in the lesser categories make out of the wannabees ART, DAMS, Campos, Trident etc.