Would it be possible for someone to develop scar tissue on the lungs?

Yes. Causes can include bacterial or fungal infection, exposure to scalding fumes or disease processes like sarcoidosis as well as many other things. Yes lung tissue is really very fragile and susceptible to injury.
Lung Scarring. Interstitial lung disease is the name for a group of disorders that can scar the lungs. There are many causes of interstitial lung disease, but usually the disease progresses causing scarring of the lung tissue. The scar tissue on the lungs affects the lungs' function and is irreversible.