>Your view seems to be that the syrian government wants its territory back but not the rebels, preferring them to flee into neighbor countries rather than resettle them elsewhere. But I have also read that the rebels are not a majority and they just hold local population hostage because they control natural resources, production, and distribution channels, and the foreign aid.
Those aren't mutually exclusive, most of Idlib's population might well dislike both the government and whichever specific rebel group lords over them. Idlib in particular was a high unrest province from the beginning and has only received more anti-government people since then. Refugees are also more likely to dislike the government, as it is rebel-controlled neighborhoods which got depopulated the most by the fighting (rebels don't have as much artillery, or else it'd be equal).
That said, even if the government doesn't want the refugees back/they don't want to return, ending the war early is still better than dragging it out. Once the war is deemed over, conditions will improve, the government might do internal changes, international pressure will relax and more refugees will want to return.