That is not my belief. In fact, my belief is the opposite for now - Assad + Russia want to get Syria down to ISIS and the government so the only choice left is Assad.Your naïve belief that Vladimir Putin and the Iranians will simply get rid of the JV team then go home represents the differences between us.
You have more in common with Neville Chamberlain than you think ...
If you'd stop making things up like above and start thinking about what we can actually accomplish you might come up with some better ideas. I have yet to see anyone propose a real good outcome for what we can do in Syria with the military going gung ho right now. There's only so much to bomb (we're already doing that). Arming people like crazy means you're arming our enemies in the long run. We don't want to fight a ground war because we are not interested in holding territory (and rightfully so). There are no good allies on the ground for the US besides maybe the Kurds, but they do not have the ability to take on both ISIS and Assad. Where does that leave us? The uncomfortable truth that I see is that we can't really "fix" Syria right now, and it's naive to pretend otherwise.
This is the real naivete - the belief that the US has some magic military wand that can fix the world's problems.
Neville Chamberlain is a worthless comparison to what we are doing in the Middle East, and you look silly when you bring it up. We are facing a very different situation (a sectarian civil war) with very different players.