[notahacker]

Shares in Ponzis are often easily transferable, as are penny stocks pumped by email spam and all the tokens and altcoins you mention that were created in obvious bad faith. Many of them have considerably fewer than 21 million in circulation too, and none of them claim to be worth as much as a Bitcoin. It doesn't make them good investments.

"If interest grows" is the big if and "price go up" is a very, very bad reason for interest in one particular coin to continue growing indefinitely when faced with all the alternative ways for people to park their money, from technically superior coins to investments they can actually live in (some available for less than a cryptographic string!) or stuff that pays actual dividends and gives you legal claim to actual real world assets. And for all the FUD cryptoenthusiasts like to spread about government money printing, it's the "fiat" world that has all the mechanisms that link money supply growth with market demand and real world activity, ability to shrink the money supply if its growing too fast, and the crypto world where basically the entire supply of coins has been printed in a few years by a small number of people trying to get rich and those coins will continue to exist for as long as the blockchain is maintained whether people want to buy them or not.