Deluxe edition is not expensive as such, when compared to other larger games like War of the Ring or Twilight Imperium, but it is more expensive than what many other strategy games are. Royal edition of Crusader Kings is in the same price range with the basic edition of EU, but then again CK does not have as many boards, miniatures and tokens as EU Deluxe edition has, which explains the higher price.
I'm certain that for many people 4 player game with two ages is more than enough. Even though I ordered Deluxe edition, I assume that most of the time I cannot find 6 players to play all 4 ages, because people have work and kids.