Im all for paying for quality, but Ive never had a burger that was worth 20 bucks. I suppose if it was fairly big and had tons of stuff inside them maybe. What I see is a lot of hipster places with weak ass burgers for 20 bucks, no fries. I can get better burgers at hole in the wall places for less than half that.
I also see a lot of build your own burgers that charge for everything. Cheese is a buck or 2, every other condiment is a buck. You will end up at 20 building a pretty standard burger.