Does anyone know why Castle Pines and Castle Rock were split as separate towns/cities?

The residents of Castle Pines wanted to have more control over the area where they lived and what businesses were allowed in, etc. Considering the beauty of the area, one certainly can't blame them. A committee filed a petition to be allowed to incorporate around 2006 and got approval to put it to vote. Voters favored the initiative 4-1 and Castle Pines became a town in 2008.