The music just isn’t there anymore. There used to be a lot of mass appeal Christian rock and pop-rock that would easily crossover into mainstream radio. Air1 thrived on bands like P.O.D., Daughtry, Flyleaf, Switchfoot, The Almost, Red, Owl City, Relient K, etc in their rock days. It faded out around 2014-2015 and they ended up repositioning from The Positive Alternative to Positive Hits. The Worship music from Bethel, Hillsong, etc started to take hold among the 18-34s, so they went with it, initially partially and finally fulltime this year.
There’s not enough mass appeal Christian Rock being pushed by the labels anymore