Pretty simple - as you make more, you adjust your lifestyle accordingly (or what you think is accordingly).
Spenders are going to be broke (or feel broke) no matter what level they're they operate on.
Savers are going to have money in the bank no matter how much they bring home.
My wife and i are both spenders. So, while our income has increased many times over from our early days (she finished school, got her masters and went to work; I caught a couple breaks here and there) ... we aren't stacking like we thought we might be at this income level.
Bottom line - people don't change who they are she their income grows. If you're bad with money, you're probably going to be bad with more money.