While you are correct that it would require pretty above median savings, it wouldn't require anywhere near $125,000 back then. Interest is a very powerful force over 40 years.
From 1949 to 1989, the stock market averaged 7.2% annually. Saving and investing only $20,000 per year for those years would net you about $5m at the end.
From 1949 to 1989, the stock market averaged 7.2% annually. Saving and investing only $20,000 per year for those years would net you about $5m at the end.