Teams are looking at guys like Grienke first, since all it will cost is money. Once teams realize they have no shot at Grienke...or when Grienke signs, then for guys like Dickey...the market will heat up further than it has already.
You do not just trade Dickey. The Mets just resigned David Wright effectively making him a Met for life. You do not want to send mixed messages to the fan base. There is a lot of talk at the meetings (at least on MLB Network) about which direction the Mets are going, and this is just because the Mets have been waiting on dealing Dickey. They are allowing the market to come to them, rather than just cutting bait and taking the best deal now (which would not include the best hitting prospect a team has). Dealing for prospects has become an art in this day and age. Teams are not loose with the prospects anymore.
If there is no team that is willing to give up their best hitting prospect and at least a player ready to play now (OF, Bullpen, whatever) than it doesn't make sense to deal him now. Keep him and play to the deadline, then see if you can send him somewhere for that same best hitting prospect you were looking for.
Just because it hasn't happened yesterday, doesn't mean something is wrong. Within the next 10 days (SA's own words as of yesterday), Dickey will either be traded, or signed.