A legal monopoly is artificial scarcity. However, if the provenance of an item is important to the buyer then scarcity of items from that source would be natural, not artificial—even if goods which are otherwise physically identical down to the atomic scale (including branding) are available from other sellers. That has nothing to do with any monopoly granted by a government. The trademark rules which prohibit using someone else's brand are there to protect buyers from fraud, not to create scarcity. As long as the buyer is fully informed as to the actual origins of the item there shouldn't be any concerns over fraud regardless of how it's been marked. Using someone else's mark in a misleading way to sell your own product would be fraud, though, even in the absence of trademark laws.
