It's sad people are so financially illiterate.

Buying partial ownership (shares) in a real company that makes a product or service profitably, or loaning money to a person or business that will be paid back with interest, are both ways to invest capital which can increase in value with no "greater fool".

Apple stock isn't worth more today than in 1990 because people arbitrarily agreed upon a bigger number, it's worth more because they've innovated and grown and now sell expensive products to a billion customers around the world.

Crypto tokens, NFTs, beanie babies, rare coins, paintings only increase in value if some greater fool comes along to pay more than you paid for it. At least with a painting or a beanie baby you could display it in your house, I guess.