The only reason Assad regime has "fallen" to US backed rebels is simply because Russia has repositioned for war.
I said this before, I'll say it again. This is NOT a good sign at all. Syria was propped up by Russian military, least the Russians have been there observing Israel and regional issues from the Syrian border..
If there was little to no resistance to the insurgency, then it's safe to say those "troops, equipment and ordinance" is being kept for something more critical than keeping Syria alive.
Oh boy oh boy