KKPS has changed formats countless times in recent years. They've gone from Tejano, to Norteno, to straight up Regional Mexican, back to pure Tejano, and now back to (what seems to be) a 50/50 mix of Tejano and Norteno. It seems that whatever they do, their target audience will always be 2nd (and older) generation Mexican-Americans (also known as Tejanos). In other words, KKPS has been built to cater to a certain culture and not a certain genre of music.
I've noticed in the past that Tejanos tolerate different kinds of music, which explains the changes. For example, KXTN in San Antonio, which is as Tejano as you can get, has added Rocio Durcal and Vicente Fernandez to their playlists. They have also given away tickets to events that do not include Tejano artists (from the top of my head, I believe they gave away Juan Gabriel tickets earlier this year).
KKPS will continue to change as long as there are new trends in music. The only difference is that they will do it with "Tejanos" in mind.