Sure you can pull out the guts and replace the inside and that will extend the life of your mods. But that isn't the point. All those extra mods have no practicality. I don't understand why people waste money turning into a piece of art. Do you and all your friends huddle around it at LAN parties? Do you ingest a couple grams of 'shrooms and stare at the glowing neons? My plain old grey case is practically a door stop. The top is loaded with a sound controller, a trackball and other misc. junk. Hell, if I didn't need access to the optical drives I would tuck the whole away from sight.
Ya, if people have money to burn, then by all means trick out your pc. But why would anyone spend a few hundred bucks on gadgets when you could get a kickass video card instead or get a nice terrabyte NAS array going.
Like I said, to each their own. Some people are vain, others are practical.