Because some people don't want 15" screen, but still need more power than Air gives you. If I were buying new computer now, it would be Air, but when I was buy

Because some people don't want 15" screen, but still need more power than Air gives you. If I were buying new computer now, it would be Air, but when I was buying my MacBook Pro, Airs were still using C2D - and since I'm using my computers for years - it wasn't really an option.