Majority of London's newly built luxury flats are unsold, raising the spectre of "posh ghost towers"

Possible on paper. Depends on whether or not the developers decide it would be cheaper to demolish the buildings, rather than sell them at a loss to recoup some portion of the investment and get out of town.

I suppose a very important question is: do they have any significant structural defects that they were expecting to correct later, after the billionaires’ money started flowing around and they could afford to cover the fixes?