@cstross @nathanael @ploum
We know from history and current events that power is the underlying drive. The ultrawealthy are not content with the money, it is the access to and exercise of power that shows their true values. I know myself the attraction to power that an answer to "what would you do with access to $X".
"Afford top private healthcare", "afford private education for kids", "live in suburb X", "own new car Y" are all stepping stones for the above-average income person. They see themselves becoming ultrarich (mathematically impossible). They become more likely to support the aspirations of the rich plutocrats.
Even in my later working life, I declared an aspiration(unrealised) to pay $500k tax per year. It was still vanity wrapped up in virtue.