Have you ever seen Star Trek or a similar science fiction story where everyone lives in a "utopia" and money doesn't exist? Always in these fictions they never seem to explain how the world operates without money, only that it does. The blockchain is so powerful that it could eventually make this fantasy a reality.
As we enter the age of abundance and cryptocurrency slowly decentralizes the wealth and resources of the world we may fail to need any sort of currency at all. We see a faint glimmer of this possibility with Steem. Here at Steem we attempt to gauge the reputation of our peers with a numerical value. I believe more and more complicated and robust reputation systems will appear as time goes on. In the end, a person's reputation might be far more valuable than the coins they've collected. We may see a shift of mining coins to mining reputation.
If these systems are good enough to stop exploits we no longer have need for money. For example, let's say in the future the only way to interact with a certain blockchain is to give them your DNA. If you're found out exploiting the system your DNA could be banned from the blockchain. The threat of being banned might be all that is needed to keep the vast majority of users in line.
Take Steem for example. If the reputation system was good enough, the power of your votes wouldn't be stake-based, it would be reputation-based. This is what I have previously been calling Proof-of-Trust and it doesn't really exist yet... but I expect it to someday.