Something that hasn’t been widely recognized is how Germany’s willingness to accept vast numbers of military age youths from Syria has facilitated the various leaderships in Syria to push toward their maximalist ethnic-cleansing goals.
Syria’s long-term problem is that it is highly diverse, with different groups that hate each other (often for good reasons).
Fighting in such situations can go on for a long time, but usually the ambitions run into diminishing returns: e.g., If our tribal enemies hold three watersheds, we can push them out of their most peripheral one fairly easily, their second most marginal one with more difficulty, but they’ll die in the last ditch to defend their ultimate redoubt because they have nowhere else to go. And that’s a discouraging prospect for militaries on the offensive.
So, eventually, all need to sit down and negotiate something that all Syrians can more or less live with.
On the other hand, if Dr. Merkel is promising military-age youths a lifetime of welfare in Germany, then massive ethnic cleansing becomes a more plausible goal for whichever of Syria’s various combatants have the upper hand at the moment (e.g., Assad/Putin and ISIS at present). Their implicit message to fighting age youth on the other side is: Why fight us when you can sponge off Merkel?