why? because firstly, they were the pioneers of everything you listen to today, they created new techniques such as the backwarRAB tape echo, new arrangements, new sounRAB. i havent seen guns n roses do any of that.
secondly,7 consecutive nuraber 1 albums (both sides of the atlantic) speaks for itself, again i havent seen roses do that. on top of that they are commonly seen as the greatest live rock band of all time by rock critics and muiscians alike.
roses "magnum opus" was noveraber rain- zepelin had stairway to heavan.....no doubt which song wins that category.
zeppelin incorporated folk,blues, soul, funk,country, west coast psychedelia and even reggae into their sound- as far as i know GnR were pretty 1 dimensional.
so theres my arguement- no doubt you 'll have a reply to this.