Buffalo hunts in MT and WY are pretty tough in that they are very restrictive and you really have to be in the right spot at the right time. The animals have to move to a spot they generally know they should not be in due to the concentrated hunting over the years.
Animals certainly get killed, but it's tough for someone out of state, particularly DIY as you would never know if the animals are there or not. Best odds are with an outfitter or someone local that can keep an eye on the herd and know when they step over the boundary. Some years a couple get killed and other years when the weather is right hunting can be pretty good.
The state could certainly increase the number of animals taken by expanding hunting. In MT and WY, it would mean hunting in the park which isn't politically viable and would require federal cooperation which won't happen. There are also some areas outside the park that could be opened as well as private land where the animals are a nuisance.
The tags are very expensive, anyone interested would be well served talking to prior hunters before they jump in.