A basic protocol for the exchange of value without a reliable third party must have characteristics similar to those that have defined the protocol for the global interconnection and that for the exchange of data packets, also without a reliable third party:
- (constant) decentralization
- (tendency to) immutability
- Safety
- Scalability/resilience
- Consensus
Right now the only system that can satisfy these features is Bitcoin.
My dear Ethereum supporters, unfortunately yours is not a useful system to build on it just because it violates all the features listed above.
Ripple? It lacks decentralization and therefore immutability and security, not to mention Consesus, but it is highly scalable. Can it be a good basic protocol for the exchange of value without a third party? No, due to the lack of other necessary features.
Monero and Litecoin? They are approaching, but the trade-offs are such that, if the networks saturate, there would be a lack of decentralization due to the size that their blockchains would acquire (for Litecoin due to the size of the blocks, for Monero due to the architecture of the code, onchain-fungibility oriented).