The shoes would be free and not a market product, as is it currently air to breathe.

Free market is just the best way we know of dealing with scarcity, every other alternative that was attempted seems to fail sooner or later. If you invent a way to get an infinite amount of something, that something goes out of the free market rationing.

For the knowledge, a lot of free market more radical defenders don't believe at all in current state of "intelectual property", much less if et has to be enforced by the state. They are for "industial secrets" (if they leak, you lose them), NDAs (if they leak, you enforce the contract) and similar formulas.