Right handed vs left handed things

[Vehn]

This might be kind of stupid but.. why are many two handed things the way they are? By that I mean, why are the most important things done by your left hand when your right hand is the "better" hand. Two examples: guitars and game controllers. Wouldn't it make more sense for them to be switched? Wouldn't fingering a guitar be easier with your right hand while you strum with the left? What do left handed people think about this? Are left handed people better console gamers than right?