I propose that credit card debt is simply the earliest signal of "not making enough money to sustain the life you think of as normal."

We have not yet come to terms with the fact that the overwhelming majority of people outside of a tiny sliver of elites are going to be lucky to afford bare subsistence in the years to come. Credit card debt lets us delay confrontation with the reality that wages have not grown enough, employment is not strong enough for most people in middle-class jobs to live the lives we used to think of as middle class.

Of course you reach for plastic before you stop buying groceries.