I'd add one more point regarding the "noble savage" excuse the technology gap keeps landing on.

The Na'vi *can't* be more technologically advanced. Since the planet is almost completely alive and the Na'vi plugged into it, they can't put a shovel into the ground without killing something dear to them. For them to make an advancement at the detriment of something living, it would have to be worth it to them. Eating to survive is worth it, so they have thanksgiving at every kill, but kill nonetheless.

The one exception I could think of would be digging unobtanium off the side of one of the floating mountains to create some sort of flying vehicle. But they already have flying vehicles that perform their own maintenance! And the superconductor hovering would only work in highly magnetic regions.

So I'd argue they are technologically advanced. They have a standing army, worldwide network, flying vehicles. Their technology - carbon fiber skeletons & fibre optic adapters come naturally.

One counterexample to your point is worth mentioning: Startups driven by ex-academics. There are case studies of successful ventures where researchers came out of the university and into the private sector to apply research to commercial problems. They are niche, but perhaps that's how you could clarify your assertion - by also mentioned niche solutions based on solid research.