Pulmonary surfactant and lung collapse

I had a question on pulmonary collapse and surfactants

I know that surfactants reduce the surface tension of the alveoli fluid because by adding the surfactant the hydrophilic molecules are able to move away underneath this surfactant if we apply a force and therefore they aren't that resistant to a force so we are able to inhale air without exerting an extremely high pressure.

What I don't understand is why would lungs collapse if we did not have a surfactant? Is it because the molecules...

Pulmonary surfactant and lung collapse