As much as I love HK (and I do) I just can't see it as a sustainable option in the future. Who can afford to retire here and actually live well? Maybe retired bankers or people that have got in early on the property market. That's certainly not an option for me. I don't want to wait till I'm too old to adapt or be employable in another country before I find my way to the airport.
In an ideal scenario I would definitely come back to HK from time to time (winter, of course). I have a great network of friends here, indeed, that will be the biggest wrench of all.