Lets say that this act to form the national park failed. What may happen to the area of Yellowstone next. How may its use and development for homesteads and mines affect the USA. Also in what ways could the exploitation of its resources cause butterflies. Could large cities be built in the area, eventually tapping into its geothermal energy as a power source?
I'd image that a few specie still alive in OTL may go extinct and individuals like Teddy Roosevelt will be pissed off by this so add your comments about such possible butterflies as well.