I own only 4 designer bags - two YSL's, one Celine and a Lanvin, and I bought all of the barring the Celine at a discount of north of 60%. I don't own any Chanels or LV's or Hermes', and don't think I ever will either. I don't buy to show off, if anything, I feel terribly self-conscious when I carry my expensive bags on special occasions (and they ARE reserved only for special occasions; I don't carry my chyc cab as when I'm on my coffee run). I don't but 'it' bags, I don't buy monogrammed ones ; I buy bags which I personally find beautiful.
The thing is, to an extent, you get what you pay for. Sure, some brands are outrageously marked up, but personally, I don't find the idea of spending $750-$900 on a beautiful leather bag which will last me decades a silly thing to do. We probably spend more on ephemeral things like booze, cigarettes, food, night-outs, make-up etc in one calendar year, and these things last for what… a couple of hours at the most? Sure, you can get a canvas bag for $20, but it's hardly going to last or look good ten years down the road, is it?