OK then, so we move everyone out to zone 4 so that the property they vacated can be bought up by people in Singapore and left vacant. What problem exactly have you solved, other than the one where you were irritated that someone was living in an expensive flat?
If we go back to my original proposal it was to build more housing. The problem is the housing waiting list - managing housing on a London wide basis and making efficient use of it could make a significant reduction in that list.