I agree it looks extortionate but of course if there was no charge you'd have to have a very large waiting areas as people would arrive early or wait until people get out from airside - LHR used to have that problem at all their terminals 20 years ago.
i'm sure they'd say you're paying for the convenience of not using public transport to get you to your destination or somewhere cheaper to be picked up.
Its really just part of the democratisation (or Ryanisation) of the airline business - 60 years ago you were special - now you're treated as if you where on a local bus - you get what you pay for.............. if you're rich enough you can still get a car to the steps of your private jet