How much will transaction fees eventually be? describes that current transaction fees are untenable. The transaction cost for users, I think should be the only upward driver for the price of bitcoin. Ripple has played out the transaction cost economy by centralizing the transaction processing (if I understand correctly). But, this is because traditional banks already have a real 'reputation to uphold', which is of course a reputation of paying enormous fines for untoward doings. Anyway, what coin offers a decentralized ledger, without the mining and transaction costs?
If any DLT is working without mining, then it is vulnerable to frauds, double spends, because there is no gaurantee that the nodes are honest upon block broadcasting, and no way to reach consensus between the nodes. This is only feasible in private blockchain if at all.