The idea that the rate of return on an asset has to beat the inflation rate to be meaningful has been around for far longer than 50 years. No one 50 years ago was telling you to stuff cash under your mattress or to keep your money locked up in a checking account.Well, for starters, you just did. Because guess what? It is stupid to save anything beyond a very small amount of cash for emergencies. This was not the kind of advice given by financial advisors 50 years ago. Because in a world where your money wasn't constantly losing value (which was the assumption back then) saving makes a lot sense as part of a diverse portfolio.
Your money has been "constantly losing value" for far, far longer than 50 years now, so that wasn't "the assumption back then" anyway. Inflation didn't suddenly start its existence in the 1950s or 1960s.
Edit: If you mean "saving" in the sense of bank deposits, I meant saving in the broader sense of "investing." Putting your money in the bank today, with the rates not beating inflation, is stupid. Investing your money in assets that are beating inflation is not stupid.