The new lot are less organized than Iran, and have less in the way of financial resources, as they have to beg for money from the Saudis and the gulf. Their paymasters are not at this point inclined to facilitate wars against Israel.
The rebel groups absolutely dont have a source of income, they are beggars.
As for existing Syrian armaments that they could “inherit”, I understand the Israelis have been working on that.
Did you watch the video to the end? They don't look "less organized" to me, nor do they look like they're hurting for money, food, ammo, or anything else. In fact, they appear to be about as well organzied as one could expect, a battlefield being what it is.