Technology can alter these economies, and I am certainly not saying we should all go to subsistance farming to avoid the paradox. I think making the calculation "equipment=making X lives" is a little off the mark: typically, you'd subtract Utilions (if you are trading for the mining equipment) and add workers. (for repair/maintainence) so you might end up with, say, 12 people, 10 who mine and 2 who repair, and 85 utilions rather than 100. But the end math of who gets how much ends up about the same as your hypothetical.