Capitalism attempts to distribute the wealth produced by the nation according to the value each individual (and that individual's property) contributes to the economy. There are false positives and false negatives there (people who make more money than their contribution is worth and vice versa), but that's the theory.
A fundamental assumption of that system is that almost everyone (apart from the sick or handicapped) can produce enough value to sustain themselves. Even if someone has no capital or no education, we assume that they can trade unskilled labor and that the value of that labor suffices to buy them, at least, the things they need to satisfy their most basic needs.
That assumption might become untrue in the future. If that happens, the problem won't be that we don't produce enough value to support these people, but that the current system for distributing that wealth will no longer work.