Not by choice. Stocks are pushed onto Americans (as well as Europeans, and most people in the West) via their pension funds, advanced savings accounts, and sometimes even their salaries (via options). If normal savings accounts in their local credit union would offer adequate interest rates (and if paying in stocks was outlawed by their unions) stock ownership would plummet. I would be surprised if it would even exceed 2%.
That’s a good thing!
Anywhere else you put money as an investment will barely match inflation.
That feels like a disadvantage by design. In a different (and more fair) economy, investing in government bonds or a savings account in your local credit union would give you a better deal then leaving your money with a global hedge fund conglomerate which in turn invests your money into all sorts of unethical companies, including oil and weapons companies.