This article suffers from hindsight bias by virtue of focusing on the US stock market, for which this has been an exceptionally good century. If you were to include the markets of Britain, the Netherlands, Japan, Germany, France, Poland, China, Argentina, and Switzerland, the picture doesn't look so rosy. Anything you invested in the Giełda Pieniężna w Warszawie in 01926, for example, would have evaporated in 01939; despite the "liberation" of Poland in 01945, no stock exchange would reopen there for 50 years.

Poland is an extreme case, but so is the US—I don't think any other country's stocks did so well during the 20th century. If someone were to write an article about how well Esso/ExxonMobil stock has done from 01926 to 02021 (11.9% I think), it would be easy to understand that this wasn't a recommendation to hold ExxonMobil for the next century, much less some other arbitrary stock; obviously the investors 95 years ago in the F.W. Woolworth Company and the Kennecott Mines Company didn't do quite as well, which is precisely why nobody would write an article today about buying and holding Woolworth's stock.

Will the US do so well over the next century? The spectacular bungling of the covid pandemic suggests that it may not.