It's a combination of many factors. Over the last 50 years or so, the median salary has barely kept up with real inflation (the CPI is set up to ignore increased prices if the product is improved, which all tech products are, by definition). Higher education, housing, and health have both seen far greater price increases than the CPI.

Add to that, Americans are bombarded with ads, with some studies estimating the average American sees over 4000 ads a day. All this invites people to spend more today at the expense of their tomorrow.

Finally, credit is super easy to come by, and card issuers set things up to make it harder to get out of debt through too-low minimum payments, too-high penalties, and until the law changed a while back, using accounting tricks to maximize interest, e.g.,by applying payments first toward low-interest balances.

People now in their late sixties didn't have the same protections against cars issuer abuses when they were in their twenties and thirties as we have now.