Yes, this is your standard 'overthinking-stargate' post.
But given that the main rival to Jaffa and Goa'uld forces would traditionally be other Jaffa and Goa'uld, the primary (or secondary, second to policing civilians) threat would come from air assault and assorting air-support, given that Ha'tak could land, or bring gliders or both, and Al'kesh could show up independently of Ha'taks and gliders, you'd think that Jaffa would have ample air defenses. But as far as we've seen in the show, they don't.
What would complete the setting in that regard? Should they have had some sort of MANPADs? The ring-threading round gliders seem like the obvious choice, but they do not apparently make them as they once did, for some reason.
Well given that the Jaffa operate strategically pretty much the same as the Goa'uld their main air defence is what you already showed in your OP: the glider. And beyond that any other Goa'uld ship they can get their hands on.
But yeah, in the show we see MANPADs, air-to-air missiles, and even an unguided rocket launcher being successfully used against gliders and other small to medium ships. So deploying them Patriot batteries to Dakara would have been a good idea probably. Also those AA railguns (?) that get used at the battle for Atlantis at the end of season 1.
Ancient drones would of course be king if you could get a production chain for ammunition and a launch platform going, those things just shred any Goa'uld ship (or other ship for that matter) if you have enough. In lieu of that Asgard/Tolan energy weapons should be the most effective air defence, save for the nastier opponents smart enough to adapt shields on the fly like Replicators and whatnot.