In your first scenario, the average rent has gone from $1000 -> $1333, so I'd say a 33% increase. In your second scenario, the average rent has not changed. I

In your first scenario, the average rent has gone from $1000 -> $1333, so I'd say a 33% increase. In your second scenario, the average rent has not changed. If this supply change happened over a century, a 33% increase would probably be very reasonable, and means the price went down in real terms.