I agree that there are plenty of these people but many have got to the stage where they have been away from work for so long they feel they cannot face work any more. And, let's face of it some, possibly many, of them would not be suitable employees anyway- there are plenty of keener or more able people who are looking for work also, so maybe we just have to accept the'cant' work, won't work' brigade.
I do feel though that something should be done in return for benefits, even if it's just a few hours unpaid community work a week, but this is probably never going to happen for all sorts of reasons