I can't speak to that since it didn't happen to me, but several of those who offered assistance were also women so I'm not sure it was a "shining knight rescues damsel in distress" response.

yes. have you been to tokyo?

i was offered help multiple times when standing alone by myself when waiting for something, or someone. i'm an asian male, pretty much indistinguishable from any random japanese guy.

i've been a lot of places and i have a hard time believing that you could fall down in the middle street anywhere on earth and nobody will help you, including new york, shanghai, other megacities.

excepting maybe some extreme examples like communistic societies at the height of the cold war, but that's it.