Traditionally, doctors use gestational age, the number of weeks from fertilization to birth, to determine whether a preemie should receive invasive care.
Look, these are preemies, people. They were supposed to have spent another eight weeks in the womb. Just like interns, they're not ready for the real world.
Preemies' lungs haven't yet developed enough of these surfactants, so the small alveoli squeeze too much and collapse, while the larger ones keep blowing up and get distended.