The idea of running commercial services inside a national park seems to me to be ridiculous as a concept. The idea that a strip mall with grocery stores, hotels, and gas stations (and yes they have that in Yellowstone) is "national park" land makes the concept of a national park ridiculous.

Why not just take the areas inside national parks that are currently commercially developed, remove them from the park, and sell them off to private owners. Now there can just be a law that you can't build a damn thing on national park land, and then private companies can run commercial services on non-park land and there won't be this conflict of interest.