I think it’s possible to achieve but, as Shagnasty points out, it requires more than just technology for it to occur. Even if we essentially happened upon virtually free and unlimited energy and other sorts of fantastic technology like replicators, we will still need a fundamental shift in the system for it to happen. Our current economy essentially works on the idea that people will be looking out for themselves and produce something of value to get things they want and need. In such an economy, even if we can produce things nearly free, we’ll still have some jobs that need to be done by people, like maintenance, leadership, research, etc. and we’ll need enough people willing to work those jobs without an ultimate goal of self interest. Of course, we can hope that in the same way that some people will be poor now to pursue a particular dream, not burdened by a need to feed and clothe themselves forcing them to work a job they hate, we can hope these jobs that are still necessary will somehow still get done, but I’m not so sure enough people would be interested in getting the training and education it would take to, say, work on maintaining a harvesting machine.
And there’s going to be a transition period no matter what, and that will be the most difficult part. Right now money is what our economy runs on and in such a theoretical economy, money is essentially worthless, but where is the transition? Someone is going to have to foot the initial bill to put in infrastructure. Until all the jobs are automated, who puts in the work to get that done and why? As we automate more and more jobs, money will still have some worth and people will need it, but we’ll have fewer and fewer jobs for people to do and so less ways for people to get that money that need during that transition. That is, in essence, we’ll be raising the minimum living standards, but in so doing, we’ll make the lower class larger and larger. Until we get to a point where that group is sufficiently large and those standards are sufficiently good, there will be enormous growing pains in that transition.
And even if we could make all the necessary discoveries were made today, people in positions of power, particularly the wealthy or those in charge of resources or industries that would be threatened by such a shift, will likely have quite a bit of say in trying to prevent it. Those people really have nothing to gain from moving to such an economy since they more or less already have unlimited access to whatever they want, but they’ll likely have to give up some amount of their living standard and most or all of their status to accomplish it. They have nothing to gain and everything to lose, and yet they’re the people we would most need on board to make it happen. Barring a situation where we have a plethora of altruistic billionaires and corporations willing to do it, I’m not sure how we accomplish it short of force, which sort of defeats the whole purpose.
Still, I think it’s something that can be achieved at some point in our future if we don’t self-annihilate first, but considering that the necessary technology is not only well off but not actively being researched and the necessary changes insociety to make it work would probably take many times longer… I think any estimate short of a few centuries is awfully optimistic.