Because its so much more fun camping a mob for hours at a time, killing the same mob over and over again just in the hope that in 1 of the 100 kills you the item you want will drop, right?
Yes, why should party play be encouraged!?
Because we all love other players blocking entrance and getting in the way when we're trying to get about.
Surly it can't take long to completely re-model and entire world!
Is teleportation not an efficient means of transport? Sure, Chocobos and Airships look cool, but from playing FFXI I seem to teleport spells and outpost warps being a much prefered method of getting around.