In 1980, the median size of a new home in the U.S. was 1,595 square feet. 44 years later, the median size of newly constructed homes was 2,514 square feet (2023).

Plus, many homes in the 70s & 80s were sold with unfinished basements (growing up, my "bedroom" was a corner of the unfinished basement for years), and I think that's relatively rare nowadays.