"...I don't think they even realize that elderly people are standing."

It isn't just kids who are like that. If anything it's people in their 20s and 30s who are worst.

Actually I get the impression, as someone who doesn't get up to London that often, that things seem to be getting better in the London Tube more recently - there are a lot more young people around from overseas with a bit more awareness of this kind of thing. It'd be good to feel it might rub off on the natives, but perhaps that's too much to hope