Syrian army never really even tried to hold their positions (and they had hundreds of them) so I guess many of them were also tired of all this. You don't just lose your fortified positions after 10 minutes to some rebels on motorbikes. We could also read about town after town to have an agreement with the rebels to hand the place over to them.
It wouldn't surprise me if some of Assad's regime changed fronts so that this was so easy for the rebels in most towns.