Professors are greedy

Many of the professors I met suffer from greed. Of course, there are fields where professors don't make much money and they are simply forced to live a frugal lifestyle. But the ones that I met were making well above 100K a year for sure and yet were driving old rusty cars and wearing washed-out 3 dollar t-shirts to school.

I think the roots of this problem lie in the PhD program. Most professors have to undergo years and years of poverty before they become profs. So being frugal becomes a permanent trait.