That's the crux of the matter.
Everyone except Ian has moved on.
Whilst his massive contribution to the scene 30 plus years ago is unquestionable - he currently has no influence on the scene other than as a bit of a laughing stock to some people.
Unfortunately for Ian, he doesn't have either the good grace or common sense to know when he is on a hiding to nothing, and that by being a little more humble he could have made his mark again.
Insulting everyone on Soul Source has done him no favours, in fact it's probably galvanised ill feeling towards him, and brought a few more 'anti' Levine members into the camp.
He's making himself into a very bitter and sad individual, for the sake of his mental health I'd recommend that he dropped any connection with the 'Northern Soul' scene and concentrate on something more positive.