The most difficult task for a songwriter is development of the melody. The melody of a song has the same function as a theme in an orchestral composition.
Writing melodies is so difficult that most writers of praise choruses have decided not have a melody. Instead, they opt for sort of a hybrid vocal chord progression and chant. That is a million times easier to produce.
Apparently, if you take the time to write a melody, then you can’t crank out praise choruses fast enough to dominate the market.