The entire world was taken by surprise when Putin ordered Russian ground troops out of Syria. They’ve been fighting the enemies of Bashar Assad.
Nobody seems to be crowing over this, most people are just surprised.
Everybody speculates about why. I’ll add just one more theory, that Putin calculates that Assad will last at least into 2017, and he wants to take Russia’s presence in Syria out of the 2016 presidential elections noise, and then review the situation after November.
That has got to be one of the factors he considered I’m sure, anyway.