Why do premature infants have severe respiratory problems due to lack of surfactant?

Surfactant: You answered that question, it is because of lack of surfactant . Surfactant is needed for surface tension, it keeps the lungs from collapsing.

Specialized coating: Surfactant production is one of the last things to develop, like paint for your rooms, you get everything else built before the finish work.Prematurity or maternal diabetes can delay production. The material works on the walls of the air pockets in the lungs to keep them partially open when you exhale. Without the coating, these air pockets empty like a balloon & take excessive force to reopen.