I'm cheap and a slow-adopter. There weren't CO2 cartridges available in the '60s when I started; they don't do anything that a pump won't do and they do have other drawbacks as noted above. As such, I'm unlikely to change my stubborn ways.
Heck, in spite of getting a flat about once every five to ten thousand miles, I still carry spare tubes, a patch kit and some dollars (tire boots).