Syria is a very... modern.. war.
I don't mean that in terms necessarily of the weapons used but in the political realm.
Back in the 90s American's saw their troop's bodies being dragged around the streets of Mogadishu after being captured and Bill Clinton in response changed they way things were done. The film Blackhawk Down is based around the prelude to this.
Rather than uniformed soldiers on the ground things were contracted out to mercenaries. Or contractors as they are known.
Most of Iraq for instance was turned into almost an ex special forces hunting lodge where the contractors were immune from being charged with murder or anything else, so long as they used rifles less than 50 cal in size.
Hence no Hague convention rules on hollow points or other ammo prescribed against in actual war, so long as you were using something less powerful than an anti aircraft cannon it was fine.
Which oddly enough became a bit of a problem, especially when some of them were videotaped shooting up civilian vehicles for fun.
This was mainly paid for by Iraqis, rather than the American government. And the casualties ( sometimes western contractors were pitted against each other) both civilian and ex military were not newsworthy, not reported.
You could describe at least 12 major groups in Syria, all supposedly fighting Al Nusra, ISIS and the official Syrian forces. So with Russia, the USA, Gulf states and many EU states all bringing firepower to bear you'd think it should have been a short affair against poorly equipped forces.
Trouble is that other than the Assad forces, the Russians and the Turks all parties were and are basically mercenaries. You'd get the religiously indoctrinated types, including from here, but the vast majority of combatants worked for a day rate, reportedly and more recently admittedly provided by the Qataris ( and the Saudis, though they haven't actually admitted it, instead blaming the Qataris after they did).
So you'd hear ISIS defeated in x, when all this actually meant was that a bunch of mercs had slotted another bunch of mercs. So ISIS ( or whichever faction) being then short would raise their day rate, contractors would swap sides and so the merry dance continued.
The American's for instance provided $500m to arm and train fighters. Who once armed and trained went to anyone who paid them more. Hilarious scene from a Senate committee where a General has to admit that their half a billion dollars bought them 5 blokes.
Only the Russians with their diabolically clinical logic really found a way around this.
Hence... The propaganda on all sides which tried to paint the conflict as a traditional state on state affair, was always doomed to fail.
Islamic state, no matter how more evil than the last really evil person we deposed Assad was, or is, revelled in their blood thirsty image too much. It was obvious that bombing Assad's forces directly or indirectly helped ISIS.
So who is ISIS if their opponents are mainly mercs? It's the ex Iraqi army that we disbanded over night, who became contractors as no longer employed...
Meanwhile sticky Bill's policy has actually ( bear with me here, it's a stretch but think like a politician) been a great success... You don't hear of British 'contractors' dying out there or previously in Iraq itself. Nor of who funds them. You do hear of radicalised yoofs hotfooting it to Syria, but no-one expects or thinks ex forces types do or did the same.
The whole military contractors thing has grown into rather a large industry, though a murky one you rarely hear anything about.
Syria however is the result.