It seems to me that for the minimal effort of saying "That's a little steep, any chance of getting a break on that?" it is well worth the effort if the agent says "Let me see what I can do" and comes back with a lower upgrade cost.

I've haggled for real in the Casbah in Fez and since I don't normally have a few hours to spend going back and forth with a ticket agent, it seems that your characterization of this is a bit off the mark.