I don't think that we can say the Ophions don't have advanced technology. For all we know, they could look down on us for being dressed, which is a thing only savages would do in their society. Also, the few LGM we've seen might very well not be representative of their entire species. Imagine a bunch of aliens landing on Earth today and being confronted to a few guys lost in the desert. Could they say with certitude that the human race knows nothing about technology?
Of course, on Earth, there are plenty of facilities observable from space to determine our technology level, but what if the Ophions were so advanced that they could hide it to the human eyes, Wakanda style? Or it could even be underground, and we'd be none the wiser. As for me, I still think that they're living in a hivemind society where the main female is assuming direct control!