I've never gotten a satisfying answer to this simple question.
I've always expected something practical for the reason. "The joystick is on the left side because ____" and that'd be the end of it. But, no, the replies I've gotten usually range from "because it is" to "suck it up, get used to it." I've never done the arcades. I've played controllers my whole life and within the past few years, migrated to PC with keyboard and mouse.
I've heard reasons like that your right
hand is more dextrous and able to do the complex button inputs. But that's not true as shown by this Starcraft
video. PC players use their left hand for complex key inputs and their right for mouse movement so that argument is weak.
Then there are replies like "Go make your own fightstick" which completely ignore the question.
I would get frustrated sometimes and literally flip around the fightstick and pretend
to use it with my right hand, feeling it more noticeably natural and instinctive. I've had suspicions that being left handed would be an advantage (at first). We use so many things right handed so why is something as complex as motion inputs given to our weak hand?
I'm not familiar with arcade history, but my guess is that it has something to do with the network effect
. In basic, the more popular something is, the more useful is becomes. The more left handed joysticks there are, the more people have to use it to play, then the more left handed joysticks are made and so on, becoming a self-perpetuating cycle.
My favorite network effect example is the QWERTY keyboard which many people don't realize may not be the most efficient
player. Open your hole wide 'cause my DPs are perfect now.