This is spot on, but one additional factor that makes me desire a high-res DSLR is because I know one day we will have retina wallpaper and the billboard use case will be real and mass-market. I would like to capture as much data as possible in the camera so I can re-enjoy the scene in the most immersive way in the future.

Most of the pictures I take are most definitely not art, just an attempt at snapshotting now.