IIRC Nixon also complained that all anyone remembered of the Checkers speech was that he used the little dog as a tear jerker. he used to complain that in fact he also trotted out all the numbers for disclosure and showed that although he had a decent slush fund for advertising and other campaigning expenses (a PAC by any other name) he never took a dime to enrich his own pockets.
I also read that he used his poker skills to get fairly rich while sitting around the south Pacific in the navy during WWII. Again, the type of smarts that work well for a politician work well for many other endeavours, and the connections and name he made in politics also, obviously, helped him get a very lucrative job when he needed one.
Plus he was golfing buddies with the guy who invented the spray can nozzle (Robert Ablanalp?) so I imagine his billionaire friend picked up the tab for a lot of their outings and vacations.