While I agree that the behaviour you wrote about is reprehensible, please do not trivialize depression. Perhaps if their mental health issues were easier to treat, their impact on the society would be more positive, dont you think so?
I've seen the differences in the US as well. It was an interesting being a fly on the wall at a gym where old and nuevo riche worked out.
The main difference was how they treated others outside their class. Old school folks usually didn't flaunt their worth, were respectful, had manners and raised their children as well. Many were willing to offer valuable advice and such once they knew you.
New? Treated people as disposable, parked in fire and handicapped zones, littered, and had a pack of spoiled brats. You could smell the attitude. I wanted to drop them without resources in one of the lower class neighborhoods or a disaster zone for a week, just so they would realize how lucky and fragile they were...
The thing is that this breed exists in every city in the world - what exacerbates the situation in Delhi is that they don't have any regard for law and order. Couple that with the relatively weak and easily bribed police force - you have these kids running over pedestrians and getting away with it, shooting waitresses in the head when they deny them drinks after closing time (as an extreme example)
I don't care about their depression problems, a good ass whooping can fix that, I care about the unsafe environment they create in the city.