I predict eventually a chain that doesn't require PoW will gain popularity.
Also, the chain won't have to be a store of value. Instead the value will be real assets represented as "tokens".
The asset can be anything. Stock, royalty rights, water rights, futures, commodities, etc.
The ledger would then act as an exchange/settlement layer that can match trades. Merchant denominates prices in shares of GOOG, customer pays with AAPL.
It seems like currency is largely helpful for providing liquidity for trades. It's hard to trade goats for camels if the other person doesn't want goats. The ledger I believe can help get around that.