Arrogance and narcissism is just what today's parents, at least in the US, teach their children. That they come first. That they are smart and good and that the most important thing is that they love themselves and respect themselves. What did we expect to come from that sort of upbringing? Kind altruists?
I'm not even sure when the term "self-esteem" began to be used outside of psychology books. I don't think I ever heard that term at all until the late 80s and never in common usage. Nowadays I see kids actually using the term. WTF? Self-esteem has become our new god. Loving ourselves our highest value. It used to be that boasting about yourself was considered a demonstration of poor character. Now it is expected. Even demanded. Modesty is considered a flaw.
This is a failure of our cultural values and has absolutely nothing to do with iPhones or Apps. Nothing to do with computers or any other modern gadget. MySpace/Facebook are just symptoms and not the cause.
I do think Facebook encourages narcissism as well as attracting people who were already arrogant and self-loving. My first reaction to Facebook (and MySpace) was something like, "Make a page about myself? Why? Who would care? Am I really so interesting that I have to publish a page about how great I am?" I found the whole idea repellent and I still do. Obviously the Millienials don't typically share this view. Probably because they were taught that loving yourself and boasting were positive traits and that modesty was very much a negative trait.
I recently was advising a foreign student about how to act at an interview at a US university. I said, "Don't be afraid to boast. Here in America it is both expected and desired." If you don't speak highly of yourself and sing your own praises then there is something wrong with you. Luckily it is not yet like that in every country, but it may be eventually.
I'm an atheist, but I can't help but think that religion did have some effect on curbing the natural selfishness of human beings. It was a way of brainwashing people to be nicer to each other. It was all based on lies, but it may have resulted in a better world overall.
Not that I think Millenials are so terrible, but they do seem a bit more selfish, self-centered, and myopic. A bit less likely to care about others. A bit more focused on me,me,me. To be fair it's how they were taught to be. When it comes to an "every man for himself" attitude I actually think the US does pretty well compared to some places I have lived, but things do seem to be getting worse.