Reminds me of a German saying I can't quite remember (something like 'erber, gerber, versterber'). Basically the first rich generation is very frugal because they had to work hard to attain it. The second generation maintains it, not really adding more but not frittering it away either, and the third generation throws it away on ski resorts and fancy cars.

That's also one of the few things I do respect about 'old money': they really drill it into their kids to not be ostentatious and wasteful with the familial wealth, thus escaping the aforementioned trap.