That might have a lot to do with where you are. We are on the NJ Shore, a short ferry ride from downtown NYC (Wall Street.) It is not uncommon for us to see buyers move from 500K to 800K- 1M, but I don't know that is the case everywhere. Not everyone in this area does that! We have many happy homeowners well under those price points. We just don't find it unusual when a buyer does make a substantial upswing. We always work with our buyers to get them prequalified, so our efforts are in the right direction.
I suspect the price jumps and price ranges might be narrower in some other markets. We have a lot of homes in the price range you are discussing. In other areas, where that price range may be appealing to a smaller segment of the total buyer market, I would guess there might be incremental moves.