Directly? Obviously, that’s pretty rare.

But housing is something like a game of musical chairs. If Alice moves into a luxury unit, that leaves their old unit open. Bob then moves into Alice’s old unit, Charlotte moves into Bob’s old unit, Dave moves into Charlotte’s old unit, etc. until Zoey moves into Xanders old unit.

The question isn’t ‘how likely is Alice’s old unit to be affordable?’, it’s ‘how likely is it that Zoey’s old unit is affordable?’