that doesn't simply mean that eventually we'll run out of things to do. Now money that was once spent on a noodle cook can be spent on something else.
That assumes that there's something else on which to spend the money, and that those other things will have a value for which people will want to pay; none of those assumptions are givens. The observed effect is that this money will concentrate on a few hands, the only ones with access to most of the produced goods.
Socialist types will never understand or accept this, but the market will reach equilibrium.
Oh, we understand it, we simply don't believe it without the proper amount of support; exceptional claims require exceptional evidence, which that model doesn't have. Right now that argument is an unproven emotional belief, not a scientific certainty.