Yup. The movie basically set the tone that the galaxy was ruled by decadents that were kind of unaware and feckless when it came to novel challenges.

On top of that, SGC figured out that sending scouting parties of 3-4 people was insanely effective at shifting the balance of power across the whole flippin' galaxy. And that was just with conventional ballistic weapons. It makes complete sense to arm counter-insurgents with what was already working, on a much bigger scale. It gives Earth and your exploratory efforts a lot of breathing room on the cheap.

The show extrapolates from there, but does the odd thing of having to make the Goa'uld super effective at interstellar warfare, to explain the conflict with the Asgard. But by that point, the SGC has looted enough tech to build a single ship, along with a huge chunk of Robotech's storyline, to save everybody.