the ergonomic advantage of left-to-right is that most players use right-handed guitars, so the guitar's cord comes out the right side of your body, and it's most ergonomic for it to be directed straight away from you to the right side of your pedal board, not criss-crossing in front of you towards the left side of your board.

And Hendrix played the guitar left-handed, so the other way made more sense for him.

>criss-crossing in front of you towards the left side of your board. No need to criss-cross the cable in front of you, you can connect the cable to the guitar on the right side and the cable will go behind you and emerge on the left side, into the pedal board/fx processor.

With your cable in your right hand, it is easier to plug into the right side of a pedal. If you were to try to do the equivalent with your left, the guitar neck would be a little bit in the way as well.

But you have to plug cables into both sides... Also you set your pedals up before you actually start playing.

Typical modern practice would be to have a pedal board with all interconnects and power set up and fixed. Hendrix didn’t do that, but EVH did. And now the internet is full of people posting their pedalboards (P&W people especially).

But you still have to plug in from the right with the guitar cord, and from the left for the card to the amp. So I dunno, my theory may be bogus. But this pattern got established very early on, by the late 60s st the latest.