So a basic problem arises when this belief causes people to vote against their interests for policies that benefit the actually-rich to their own (incorrectly expecting that they will be rich next year) detriment. Tax cuts for the rich and for corporations, dismantling programs that benefit the poor and middle class, defunding various public institutions, etc.

It's fine to strive to achieve as much as possible and earn a bunch of money, but the core of the issue highlighted by that quote about "temporarily embarrassed millionaires" is a sort of class-affinity with the rich that is unwarranted for most people.