Because not enough people have been scared enough to sell yet,
there is still to much hope . The down move won't break until we've seen the equivalent of Jan 13-15th  2015 when we saw 200,000 BTC trade on stamp and establish the $159 post 11/13 bubble low. Stamp hasn't seen volume like that (in pure BTC terms) since Nov 16 which is more or less the start of the current uptrend baseline of circa £3k.