Company lifespan collapsed from 60 years to under 20

The numbers:

1958: average S&P 500 tenure was 61 years 🏛️.
1965: 33 years.
1990: 20 years.
2016: 24 years.
Now: about 15 years.
Forecast for 2027: 12 years

Only 52 US companies have stayed on the Fortune 500 since 1955. Out of 500. Everyone else is gone. 💀

And roughly half of today's S&P 500 is projected to be replaced within ten years.

Structural version: in 1969 industrial companies were a third of the index. That whole category was quietly evicted.