>>508717948
>no oil due to US and turkroach occupation of extraction regions and not much other economy due to war damage and lack of external investment in reconstruction so country was extremely poor and the state couldn't pay soldiers or bureaucrats
>shallow pool of manpower due to being a minoritarian regime dependent on Alawites and some other groups for filling out the army
>Assad himself wasn't favored for succession until his older brother died and didn't really want to be the king in the first place

And that was against the infinite pool of money from the US state department, Israel, and Turkey; the infinite manpower pool of international jihadis plus angry Sunni Arab radicals within the country; and the extreme determination of all his enemies to overthrow him.