Anecdotal only (so not evidence), but the three generations thing is exactly what is happening with my wife's extended family. Grandparents came out with nothing, busted their cans, built some wealth and encouraged children to pursue tertiary education. Kids kick butt, all become doctors, lawyers, engineers, end up doing extremely well. Grandkids brought up in luxury, mummy and daddy pay for everything and generally show off how much wealth they have, grandkids end up useless.
Most of these grandkids are now in their 30's and 40's and have achieved nothing on their own at all.