[quote=Magic Magnum]
What in the world is the point of laning? Why does which line I run in matter depending on my build? They all seem the exact same.
[/quote]

The current laning structure hasn't changed ever since Late Season 1. Laning is practically the structure in which the team is built around. I remember in Early Season 1 the normal laning phase consisted of a Marksman Mid, Fighter pair bot and Support/Marksman top.

The reasoning I don't know, but it is the metagame that everybody expects people to play.