I suspect that something has changed in the way square footage is calculated. Perhaps there are more finished basements or something. I was very involved in several moves my family undertook when I was younger. I feel like I got a good sense for home sizes. Many of the ones listed for 3000 sq ft. today look more like the 2000 sq ft. houses from yesteryear.
I also think about Louis Rossmann's quest to find a NYC storefront for his repair business a few years ago. He brought a laser measure with him, to document how the actual space squared with advertisements. I don't know that he ever found a place that wasn't lying. Yes, New York and, yes, commercial, but I wouldn't be surprised to see similar tactics in place for residential, across the country.
I also think about Louis Rossmann's quest to find a NYC storefront for his repair business a few years ago. He brought a laser measure with him, to document how the actual space squared with advertisements. I don't know that he ever found a place that wasn't lying. Yes, New York and, yes, commercial, but I wouldn't be surprised to see similar tactics in place for residential, across the country.