It also depends on dividends. If IBM consistently gave dividends to its shareholders, that could add up to a lot of money.

IBM is a good dividend stock. That said, there are certainly stocks you could have bought and held over the past couple of decades (as well as many index funds) that would have had better returns overall.

But it did not.

https://dqydj.com/stock-return-calculator/

IBM has objectively been a terrible investment for many, many years.