While training is extremely important, and I cannot stress that enough, it's not like states can start requiring 100 hours of range time before you're allowed to own any firearm, nor should they. That would be shot down by the Supreme Court real fast and opens the door to all kinds of abuse.

Also the basics of gun ownership are rather simple, it shouldn't take more than 6 hours to learn the basic safety concepts (muzzle/trigger discipline, when and where to shoot, "it's always loaded", etc), how to operate all of the common gun types, and your states rules and regulations (however, concealed carry is a different beast).

The bigger issue, imo, is maintenance as people forget this information or become complacent over time. Most of the people that have negligent discharges violated one of the basic safety rules because they become too comfortable and stopped taking the same precautions that took as a beginner.