the entire basis of capitalism, trading labor for capital
Uhm, that'd be wrong. The basis of capitalism is the ownership of the means of production.
Yes, it also implies that since everyone owns their own bodies, they're free to trade the labor provided by their body - be it mental pr physical - to capital, but that is not what the ideology is founded upon.
You're entirely correct in that western societies are fast approaching a point wherein the need for low skill (ie. uneducated) labor will be zero. This means that we societies at large need to figure out how to best handle the masses of people who don't want to or cannot be educated and thus cannot employ themselves in a future where there is no need for manual labor. Personally I think that a person's ability to live and enjoy a decent standard of living should never be dependent on how much they are able to work.
However, it is important to realize that even if we agree to this, it does not mean the end of capitalism. Even if we an use machines to do work faster and better, those machines need to be built. And even though we will most likely end up at a point wherein we use machines to build those machines we will still need raw materials to do so. Even if we figure out a way to build a machine, which will produce anything we can think of, that machine will still be limited by 2 factors:
1) the resources available and
2) the energy needed to run the machine
Now, theoretically we can even eliminate the 1st one of these. But supposing we manage to build a functioning replicator, unless we figure out a way to get unlimited energy to the replicators it will still be constrained in how much stuff it can produce. As long as this is the case, meaning; as long as there exists any sort of material and/or energy-production scarcity, some form of capitalism will exist. Why? For the simple reason that if we need to utilize some finite resource to produce stuff, somebody will need to provide those resources.
Using the example of star trek, supposing we have the capability to replicate anything, I want to replicate myself an entire starship. If we have unlimited resources this will be no problem, because we can simply replicate entire starships or even fleets of starships to anyone who wants them. But if we have limited resources, producing a starship for me will mean that we can't produce a starship - or anything else using the same amount of resources - for anyone else.
That is to say as long as we don't have infinite amounts of energy and materials, we cannot simply give anyone anything they desire. So if both me and Bob want a straship, but we can only manufacture 1 of them, what basis do we use to decide which one of us gets it? There needs to be some way to determine how the finite resources are to be allocated unless you're just advocating for a model of society in which anyone can ask for anything and someone randomly chooses which items get produced (and for whom). This doesn't necessarily mean we'll always have a money based economy - simply that as long as there is any type of scarcity there will also be supply and demand, and the demand has to be quantified in some way. I can say I need a starship more than Bob does and therefore I should be the one who gets it, but need is an entirely subjective concept and is of no use unless I tell, why I need it. I can say I need the starship to explore the galaxy and seek out new materials and life, and Bob can say he needs it because he really likes piloting a starship. Both are valid reasons for wanting a ship, but if we only have the resources to fulfill either my wish or Bob's, whoever controls the starship-factory will have to decide who he'll listen.
This is where the true basis of capitalism lies: the ownership of the means of production. Whoever controls the manufacturing, controls the supply. If Bob owns the replicator, he can simply build a ship for himself no matter how good arguments I might present to him for why I should be the one to get it and vice versa. The ship has value for both of us, but the value needs to be quantified if any sort of rational decisions are to be made about who gets it. This is why we have a tool of trade, money, which allows me to say "I need the ship more than Bob and therefore I am willing to pay more money (ie. resources) for it." Even if we abolish monetary-economy, some mechanism of valuation of the needs of individuals will exist as long as we don't have infinite production capabilities.
I would argue the only thing one CAN do without having massive revolts is to simply pay the masses not to work, just as we pay farmers not to grow, because like it or not we are quickly reaching a point where the tech has made us humans obsolete.
Yes, to an extent. But note that if you're going to argue that we pay them, that implies using a currency, which in turn implies an economy based on some level in capitalism, because it requires that the goods and services on the market have a value measurable in some type of currency. So to sum it up: we're in agreement that not everyone can or will do work in the future, but you're mistaken if you think this instantly means the end of capitalism - it merely means that we will have to transform the way our societies at large implement capitalism,