There probably has a huge cultural factor that people think at first of a gun as solution to their problem. Why not a bomb? Or poison? Or car? Burn down target property? So much options, but US culture seems to strongly favor guns. There is more than just availability. Glorification of guns (and solving problems using them) in US media might play a huge influence, and as a leading cultural influence might lead to similar problems else were in the world. But yeah, I'd love to see real studies about that. But those won't be easy, including the funding part...