I dare say, though this might be inherent to identities primarily derived from culture, that a lot of the things you cite, both those that are going and those that are coming, are an identity foundation for people who have very little of tangible value going for them.
If you can't actually do anything worth a damn and you're useless to the people around you, you need to resort to taking pride in things that are essentially a product of happenstance, things that did not require earning. This can be your place of birth, your history, the religion you were most likely brought up with, or in current year, who you want to fuck or the color of your skin.
On the flipside - I find that people who do good work and/or enrich their friends, family or community struggle far less with their identity because they are defined by the real, tangible effects they can observe every day and they experience far fewer crisis for this reason. These people will also usually struggle far less when circumstance forces them to relocate, as they easily adapt to a change in scenery because the scenery is less tied to how they define themselves.
The problem is that it appears that a lot of young people are taught that their core definition ought to be derived by introspection or by adherence to something. The latter is nothing new, the poor have been made to slaughter eachother for king and country for centuries, but as you say, a lot of the typical foundations that would allow one to build an identity around largely circumstantial conditions are no longer en vogue.
But at the same time, young people aren't told that they should go out instead and do, that they should derive self-value from providing value to others and the effects they have, external to their own person - there is this weird idea that one "has" an identity, that it is something one simply possesses, pieced together from genetics, geography and perhaps consumer behavior - that identity ought to be cultural, rather than something one actively builds through the skills one hones, and from how one employs them to shape and change one's world through one's interactions.
