"Einstein had realized that no experiment involving Maxwell's equations could ever detect motion relative to the hypothetical absolute rest frame."
I guess gyroscopes weren't invented yet either.
Ed McQuarrie talks the REAL History of Stocks and Bond performance.
https://www.morningstar.com/funds/vanguard-wellesley-income-is-top-choice
Could be a great fund to start with starting in retirement and cash. Or use Vanguard Wellington and cash if you want to be more aggresive
https://www.morningstar.com/economy/what-weve-learned-150-years-stock-market-crashes
Take a look at this what has happend in past in stock market