What does the math look like to you? I mean, back when I was a teenager I realized that this century is different, I shouldn't expect to do what my dad did and

What does the math look like to you? I mean, back when I was a teenager I realized that this century is different, I shouldn't expect to do what my dad did and end up (albeit through a series of acquisitions / mergers) at the same company for 30-something years with a payout plan at the end. Sometime in 2012 I saw this article[0] which starts off: "The average lifespan of a company listed in the S&P 500 index of leading US companies has decreased by more than 50 years in the last century, from 67 years in the 1920s to just 15 years today" I doubt things look any rosier 6 years later. So what does the math look like when the firm lifespan of the most profitable companies is quite a bit less than the lifespan of someone's useful working period? [0] https://www.bbc.com/news/business-16611040 https://www.bbc.com/news/business-16611040