Might I ask why not? On a personal level, I don't like negotiating myself e.g. I don't like stores that have posted prices. On a macro level, negotiating prices is how large transactions clear such that the buyer and seller get something closest to what they want (hopefully). I do think sane ceilings and floors ceilings for prices have a place in certain situations, but I wouldn't be the best person to characterize what this sanity would be.
