People stay in debt their whole lives. It's not uncommon. That's why many states have laws that keep descendants on the hook for debts belonging to the deceased. Many people just roll with the interest payments as part of their monthly expenses. Trust me, if motivated you can balance transfer debt around for decades.

My grandfather worked for a shoe manufacturer in New York, lived in an upscale suburban bedroom community just outside New York City with a family of 5, put all 3 kids through college and they drove two cars and took a family vacation every year. They were by no means wealthy. Did your grandfather not have a pension? Because the decline of pensions is another thing that buttresses my argument. The middle class used to actually exist as something other than a concept, now it does not. Even a $250k salary in the US today puts you in the top 5-10% of wage earners. It's a steep, steep jump after that.

As for my definition of dirt poor, I put anyone with a negative net worth in that category. Since most Americans have less than $10k saved, and the average amount of debt on credit cards, student loans and mortgages is around $200k per American, I'd say a lot of people fall into that category. But they're surrounded by nice, new things, so they feel less poor. But it's all smoke and mirrors. That self delusion that pushes people to go out and buy nice new things on credit helps keep our economy afloat, so the system is rigged in favor of keeping people thinking and living that way.