No, it's useful evidence in the same way that contemporaneous fiction is often useful evidence. The first season aired from 1989-1990. The living conditions from the show were plausible. I know because I was alive during that time. My best friend was the son of a vacuum cleaner salesman with a high school education, and they owned a three bedroom house in a nice area, two purebred dogs, and always had new cars. His mom never worked in any capacity. My friend played baseball on a travel team and eventually he went to a private high school.

A 2025 Homer is only plausible if he had some kind of supplemental income (like a military pension or a trust fund), if Marge had a job, if the house was in a depressed region, or he was a higher level supervisor. We can use the Simpsons as limited evidence of contemporary economic conditions in the same way that we could use the depictions of the characters in the Canterbury Tales for the same purpose.

I read this as "anything can be used as evidence if it confirms my preconceived notions". Your anecdotes about a friend or two are just that - anecdotes.

This claim of "a single man could feed a whole family on one factory job" is misleading and untrue. It's usually the 1950s that people claim this was true and they wish we could go back to the 1950s. It's easy to show that that the 1950s were no picnic (https://archive.is/oH1Vx).

It's always some time in the past that the nation was great. They pick 1950s, you pick the 1990s. What you don't understand is that people are usually longing for a time when they weren't alive or when they were children. They want to go back to living the stress free life of a happy childhood, when your parents shielded you from all the vagaries of life.

You cite cartoons, they cite memes. If you ask them how a meme could possibly be used as evidence, they say much the same as you - anecdotes about their grandparents.