That's a meaningless number without context: The median income gain was 2000% (i.e. double the purchasing power loss) during the same period (median yearly family income was $3300 in 1950 https://www.census.gov/library/publications/1952/demo/p60-00...)
However, holding the asset itself resulted in loss of buying power over time. There is a distinction between cash the asset (the thing you hold and trade with), and income.
Holding shares in a corporation over 50 years may be a good idea (depending on the company). Holding land/house over 50 years may be a good idea (depending on the location). Holding fiat cash over 50 years is never a good idea.
And the problem is someone in society has to hold it; we can't all own stocks and houses.
If the value of my fiat money is increasing, then I will hold on to it, which is good for me. If everyone does that, then the economy grinds to a halt.
The stock/bond market is, although not always efficient, at least somewhat enabling of economic activity, whereas just holding your currency (including bitcoin) is not.
The interest rate (cost of money) simply returns to a supply/demand market equilibrium. The economy possibly smoothens out, rather than giving us artificial boom and bust cycles thanks to inefficient central bank policies.