Rocky Mountain penstemon, Penstemon strictus

How do these become THE Rocky Mountain penstemon? There are so many competitors. These flowers are about as big as penstemons get, and the plants as tall. They are common.
Penstemons are most often purple to blue. And with so many species in the Rockies, something had to wind up being Rocky Mountain penstemon. These do indeed grow in the mountains, in AZ, CA, CO, NM, UT, and WY. Black Canyon of the Gunnison National Park, Montrose Co CO, 6/20/13.