Those are just how people work out the actual price to offer; that is almost orthogonal to the actual transaction that occurs.
Because otherwise prices could never decline (because comparable could never decline) - but we know that price drops do occur.
The biggest issue is that when prices are increasing year over year, it can be hard to tease out that "prices would have been X% higher instead of only Y% if Z, G, and B hadn't happened".
Or another way to put it - if you overbuild; prices will drop, because nobody will buy/rent a crappier house/unit right next to a nicer one when both are on the market for the same price - the crappier one has to drop price until competitive, or sit empty. And sure, some people will allow it to sit empty for some time, but eventually carrying costs eat it alive.
Because otherwise prices could never decline (because comparable could never decline) - but we know that price drops do occur.
The biggest issue is that when prices are increasing year over year, it can be hard to tease out that "prices would have been X% higher instead of only Y% if Z, G, and B hadn't happened".
Or another way to put it - if you overbuild; prices will drop, because nobody will buy/rent a crappier house/unit right next to a nicer one when both are on the market for the same price - the crappier one has to drop price until competitive, or sit empty. And sure, some people will allow it to sit empty for some time, but eventually carrying costs eat it alive.