Well you still have 3600 coins mined every single day. Maybe half of those are sold. If there's no demand for 1800 or so daily, meaning ~$1m new buys per day, the price must come down.
You could easily say the opposite as well. There is demand for bitcoin by a number of people, mainly by people who are wanting to start using it. I would argue that the price declines are merely the result of "normal" price cycles of a maturing currency