On the topic of "where all da people at" check out this video:
Several things scream as the elephant in the room.
1) It is socially acceptable to wear black and white, errr expected. You may wear a muted blue/green/tan or pink but not often and will be combined with black and/or black and white but not just color and white. If you wear yellow, you are in costume. Those wearing reds are employees or tourists. The man in the pink pants is likely another player and is not an npc.
2) I believe that all of the people who are not on the streets after 8 are online talking about or working on their collectibles/collections/diorama. This one has a very strong vibe and I would be shocked if the majority of all Tokyo youth do NOT have a small shrine of collectibles. But, you were in the biggest collection of display collectibles ever, sooooo. But it follows the pattern of fitting in. I never really thought about it before your posts. However, they may have a very competent policing of the streets after hours. I know that would have slowed down my hijinks.
3) Cellphone zombies are not prevalent. This surprises me. That seems to point to everyone feeling very comfortable in crowds. Possibly is the reason they wear clothing to fit in exceptionally well.
4) The highly expressive / fast walking / or loud talking are also tourists.
5) Only tourists and employees made eye contact with you, or so it seems, if my color and action observations are correct on tagging tourists.
6) It is fashion normal for a man to carry a bag shaped like a traditional women's purse. Not manbags by any stretch of style. Not attempting to Indiana Jones satchel their way into the scheme. And far fewer fanny packs than 20 years back.
I am subscribed now. Keep em coming.