I've noticed this too... My guess would be that 
with the economy so poor and cel prices going 
down, dealers are sort of trying to "wait it 
out."  I think that after having a year or so of 
climbing cel prices, dealers are no longer 
willing to sell good cels at prices that people 
can afford to pay now, which is a lot less than 
what they could afford a year ago.  Perhaps they 
would not make a profit or lose money if they 
offer cels at the prices they sell for now.