Expenses by themselves aren’t what “pushed down” means, the term was referring to the discrepancy between income and expenses going negative, so whether someone on the top end is pushed down depends completely on their income, right? (And it might be reasonable to assume they’re on the high end already because their income exceeds their expenses, no?)

The reason the pushing down is asymmetric for rich & poor when it comes to cars is that cars have some minimum expenses that can be pretty high relative to a poor person’s income, and below that minimum they lose access to a car (which in reality pushes them down eve further). Someone on the high end might choose to spend more on a car than their income safely allows, but they actually have a choice of how much to spend on a car, whereas someone on the low end might only have the choice to spend slightly more than they can actually afford, in other words very little choice.