Been living in Tokyo for near a decade, and I can add that despite it being a bustling metropolis, it does have this silent loneliness just in the background.
It's hard to describe, unless you spend any significant time here, and the locals of Tokyo will tell you the same -- it's a cold city. With that being said, I love the place. However, if not for my cabal of really close friends, I don't think I would stay here -- and these are friends from my university days back in America.
I can contrast it with another city I have lived in (on and off for 2-3 years), and that's Seoul. In my first year in Seoul, I probably met more close friends than in a decade of living in Tokyo. I'm an introvert through and through, so unless people open up to me first, there is going to be silence. Tokyo has a way of making you comfortable with the mundane.
Seoul is just this bustling amazing city with an energy of "anything is possible" in the air. Tokyo seems as though it has already had its heyday and is on a slow, silent, but peaceful decline. I love my little neighborhood, and have made a life for myself in Tokyo, but I can't honestly recommend it as a place to move to, unless you have some deep interest in Japan or family connections.
If you are interested in the startup scene, it's here but nothing on the scale that you would see in the US. I'd say Seoul is the place to be for startups now -- the Korean government is pretty much throwing money at people with ideas.
I'll always call Japan home, but I definitely see myself leaving Tokyo in the near future, if not for another city, then back to Korea.
To give some context, I'm a male 30 something PoC.