Inflated lungs from lack of recoil, not increased inside pressure.
Air goes in but getting it out is the problem.
Almost all emphysema is caused by smoking. As digestion continues, air exchange membrane is also lost. Getting rid of lubricating mucus can also cause difficulty and normal lung bacteria or invaders grow excessively in this protein-rich environment. Emphysema takes many years of smoking to develop and strikes people in the 50's or 60's. It may take 40 pack years or more of smoking to produce emphysema, a pack of cigarettes a day for 40 years or 4 packs a day for 10 years.