Man, you look at things from the wrong perspective. It's not about how many kinds of vehicles, weapons, activities or clothes are there. It's about how a lot of "meaningless" stuff has evolved.
I can finally take cover behind a crushed car I drove in to do a drug deal a few moments ago, while a group of enemy drug dealers, who are also taking cover behind trees and walls, are shooting at me through windows of the car which is slowly starting to set on fire. I run away to hide behind a bunch of garbage cans, trying to avoid all those bullets flying around, followed by a scary sound of guns held by my enemies who are now going after me. As they approach to finish me off a mighty explosion comes their way - poor fellows die screaming as a very realistic fire guttles their bodies.
Once again I leave looking for something to eat in order to recover - but no, there's nothing but a few hobos and an empty street in front of me. I decide to call my cousin for a taxi ride and while trying to reach my crappy cell phone I spot a car parked only ten steps away. As I come to break a window and hot-wire that nice looking baby whose owner will curse my name for a next few months, I suddenly hear gun shots - seems that someone was hiding among those homeless people. A star pops up in the right corner of the screen and I set off as fast as I can. Almost there, out of policeman's sight - what the hell, why the car doesn't make a turn!? Well, it was too late to think about that as I crush through trash cans and get stuck inside an narrow alley. Seems like the front tires were popped out. Perfect. As I try to get out, screen suddenly gets black - "Hello there, officer. What a nice day, huh?"
That's just one of those situations you should be enjoying when playing GTA IV.