[zaroth]

The fundamental principal of supply and demand is that shifting the supply curve down or to the right increases demand equilibrium.

If supply has a fixed upper limit and price is also fixed at a reasonable level, then demand will always peg to the right of the curve. The economic solution in this case is to increase supply (or increase cost)

This is only considered a problem when there is a real (or perceived) negative externality on increasing the supply. I fail to see the negative externality of having more national parks which massive numbers of people are very excited to tour.