Am I misreading this: the conclusion is that the lowest earners cannot afford 40th percentile rents?
It smells like the 40th-%tile is the number that the data exists for. I would welcome graphs showing this data at other %-tiles, and whether that changes the outlook significantly.
But the report puts ~50% of the workforce below the national housing wage for a 1-bed. 50% of the workforce cannot all obtain better than 40th %-tile rents.