The MM has been lambasted by so many over his suggestion that people should forget about retirement and keep working. Actually to be precise he did qualified himself by suggesting that only if you are able and want to. Just watch, but it will be many years; in their old age, they will discover too late that the MM is right. If they think work is miserable now, joblessness is worse. Of course, everyone don't mind not having a job as long as they have money. What they don't realize is that many people do not know what to do if they are not working. They will tire of their leisure. The more fortunate ones would look after their grand kids. With a TFR of only 1.22 what is the prospect of doing that? You might have to fight with your in laws for that privilege.
I think for many the optimal arrangement would be to find part time work. They no longer need as much funds as when they were bringing up a family. Beyond keeping healthy there is must less to be worried over. In many cases, the old could be extending a helping hand to the young than the other way round.
My neighbor teaches ten hours a week at one of the Polys. He told me he is very much happier that way. Their kids are all grown up and moved to Australia. They fly back often to visit him.