Does it mean that we are likely to run out of bitcoins to buy/sell on Mt. Gox?
And right now there are no bids below $138. Does that mean that unless more bids appear, the price can't drop below $138?
Thanks.
I'm happy to award you with the Platinum Prize for the
Naivest Question of the Year 

There are bids for all possible 21 million coins on Gox, all the way down to $1, however, Gox is dying because the USG has crippled their banking services. They may survive, but the echoing silence from them is not good.