Yes, the arcologies were fun, but, they were also game-breaking, and building them completely changed the nature of the game into something unrealistic that frankly didn't really work. So not having them isn't a huge loss.
In a way they were a really neat way of ending the game. There's no natural stopping point in running a city, but once your entire city is covered in arcologies it's quite a nice way of saying "and this is done".
