Syrian morale after the heavy casualties endured in over 6 years of war from a small population base is shaky despite the slow victory over the western Syria rebels:
[There] are over 50,000 armed rebels in Idlib and fewer than 100,000 Syrian troops and Iranian mercenaries available for Idlib operations. Morale is not high among the attackers, especially the Syrian troops.
It is disturbing that Assad ended up inviting the Iranians to participate.
With such low morale among his forces, Assad will apparently bombard areas onto submission and try to roll armor-led forces forward to scatter the dazed survivors. It will apparently be a slow methodical assault rather than a blitz.
Taking Idlib would go a long way to ending the multi-war in Syria of numerous outside actors fighting for different objectives.
But if the rebels scatter and break down into smaller groups for insurgent warfare against Assad's occupying forces, the low morale of Assad's forces will make them vulnerable to bloody defeats as they try to hold the territory they have taken.
Even aside from the territory in the east outside of Assad's control, will the civil war between Assad and rebels be truly be over when Idlib is reoccupied by Assad's forces?
