Ok now when you complete either the Stormcloak or Empire Questline General Tullius or Ulfric say that they will need to be ready for the Thalmor when they discover what has happened. Why don't this actually happen?? The Thalmor never do anything and Skyrim does not get into anymore wars and if you talk to some characters they say the war is still going on between the empire and stormcloaks.

DLC is more profitable.

So is TES VI.

Hopefully we can repel the Thalmor in Skyrim, and destroy them in TES Vl

Titles have never been directly tied to one another. If we are able to explore any of the dominion it'll be as an expansion or DLC. (I say explore, because unless the Thalmor master plan is revealled and the whole world turns on them, the DLC would only be applicable to certain races, and it's silly making a story arc where only certain player races can apply)