Currency exists to motivate people into slave work and to ensure the power of the ruling class, since (unfortunately) the progress of human civilization has always been dependent on human slavery. Hell. It's the most defining characteristic of human civilization so far. The interesting thing about the next hundred years though is this;
Machines will take over all the slave work. We're already seeing this happen in lots of factories. The issue however is that the more machine slaves we create, the more human "slaves" can be "free". But instead of their lives improving, it gets worse since in our current system of rule, without currency, there's no place for you anywhere in society.
The more machine slaves take over from human "slaves" the more human suffering we will see through human poverty and the higher a concentration of wealth we will see in the ruling class.
Soon, there will be no slave jobs left.
In other words, within the next hundred years we will finally see a push from the suffering part of human civilization to eradicate the concentration of wealth (Since the majority will not have any way to actually make money), and since there is no need to motivate people into doing shitty ass jobs anymore, which essentially will eliminate the need for "rulers".
We will see a rise of intellectualism and free thinking through free education (minus institutionalization) on the internet, as well as an increase in connectivity between minds, maybe even the rise and dominance of empathy. Hopefully, eventually, maybe we will even see the realization of a society full of socially conscious individuals, all stepping forward to do their bit, with government serving one purpose and one purpose only. (If it will even still exist)
To serve the human population, instead of ruling us, which is how it currently is. We are ruled, and our police force are militarized prison guards.
When one looks at the nature of human slavery and how it evolved, it's quite interesting to see how we are actually living in a state of advanced slavery. Sure, we have good slave owners like the Australian rulers (unless you happen to be aboriginal or a drug addict, then our slave owner is a pretty bad one), and bad slave owners, like North Korea, and the Iranian oppressive regime. But they're all slave owners, and unless you have money, society will keep you dumb enough never to see this, but smart enough to do the menial tasks it requires us to do to keep society moving forward.
Either that, or human population will be culled by approximately 5 - 6 billion people, and the ruling class will remain, and get to feel really bad about what happened, but not take on any guilt cause it happened a few generations ago and "I didn't do it" :P Just like we did not, and are not reaping the benefits of the aboriginal genocide and invasion, the native New Zealand genocide, the Africa situation, the American Indian invasion. (That's sarcastic, we very much are, and we refuse to accept our place, and guilt in this, merely because it didn't happen in our immediate lifetime)
We're told our freedom of choice through consumerism and choice of slave jobs equals freedom. This slave job, or that slave job, buy this useless thing you don't need, or that useless thing you don't need. Want a job where you get to make a difference? Well you either need to be rich, need to have parents who put everything into giving you the opportunity to pursuing it without having to enslave yourself, or your parents need to be high up in whatever industry you want a good job in. (This one's a personal favourite, left over from the monarch days)
We have been led to believe that our slavery is freedom, and when anyone raises a concern, they are told to compare now, to then, and be happy now is not like back then and to be "realistic".
"Realists" say things like "Life has always been like this, deal with it" without any care for how ridiculous using the term "Always" is when referring to roughly 8500 years of human civilization. Without any consideration for the irrational idea that life seems to stop and start with the limited existence of our individual sense of self. Hell, that's barely the blink of an eye in the history of time.
The corporate idea of never ending growth itself is a product of this selfish, irrational idea. Tell me, in what place of the universe, ever, does something continue to grow exponentially without eventual implosion? Time to wake up.