Syria has too few loyal troops to control the entire country of 23 million people. At some point, they are going to need to concentrate on holding the core regions of Syria to maintain the regime even if the price of maintaining the regime is territory.
This story from The Economist sees signs of this strategy being prepared:
Radical elements among the Alawites in the north-west are said to be contemplating a plan to clear nearby Sunni villages and create a rump state that is easy to defend. This might explain recent massacres in Houla and Qubeir, both Sunni farming settlements on the fault line between Sunni majority areas and the Alawite heartland.
Assad needs a different strategy to change the trend lines. But if he can't find a strategy that allows him to continue ruling all the people of Syria, will he decide he'd rather fall back and rule just those Syrians who form the pillars of his regime?
UPDATE: Huh. Are the rebels making enough gains against Assad's whole-Syria defense to compel a retreat to the core of Syria?
The site of the worst violence in the country since a peaceful uprising against Assad became an armed rebellion last year, Homs has been preparing for more fighting as Syrian troops massed around rebel-held neighborhoods there over the weekend. But the troop buildup belied the fact that more of the countryside around Homs - which includes Talbiseh - had fallen out of the government's control.
The rebel gains may not last long, of course. But if Syria's security forces are too stretched to retake the lost areas, Assad has to reconsider trying to hold all of Syria rather than an Alawite+ core.