>>713921001
If I'm not mistaken, the various button placements are a means for Nintendo and/or other companies of differentiating themselves.
Take Sony's controller layout--as far as old-school symbology is concerned, 'O' is supposed to be acceptable or affirmations, while 'X' is considered wrong or an error. I can only assumbe a similar mentality caries over to Nintendo's controllers since almost all of their first-party games use 'A' for accept, and 'B' for back.
All things considered, it was probably Microsoft/Xbox that switched things up as far as their controllers, while third-party developers functionally made 'X' the de facto accept.
