And that was when $100 was an equivalent of 3 ounces of gold which is about $4k today. Barrel of oil and S&P500 had roughly the same price in gold then as they do today.
This website suggests $656 as a more realistic figure. Enough to survive on while working furiously on your writing.
http://www.usinflationcalculator.com/
Not sure if that calls into question your statement, or suggests that the CPI is drastically understating inflation.