"We've offered them roads, schools, medicine!"
Yeah... WhiteMan's Burden, come in and give the poor primitives our knowledge. Teach them to speak our language, try to teach them mathematics, and 'raise them up' to our level. Never asking if the Na'vi need or want it... this is Our Gift! (as long as you hand over land so we can dig these useless-to-you rocks out of it)
Seriously... what do the Na'vi need roads for, when they have road-sized tree branches/roots that can be easily traversed, as well as the sleipnir-horses and the banshees? As portrayed by the movie, the Na'vi could get around just fine without bulldozing a straight line through the woods.
Medicine? We don't see any medicines used in the movie, but we do see wounded bandaged and being carried away from HomeTree. Considering that most native Earth cultures have passed down medicinal knowledge (willow-bark tea, poultices, ways to stop bleeding quickly), I find it hard to believe the Na'vi do not have their own medicinal herbs and practices that work quite well for them.
Languages. Yeah, I'm sure English was easier to learn than Na'vianess. It doesn't seem to be that hard to learn, as several of the scientists learned it on Earth, and Sully picks it up very quickly from Full Immersion. Most Na'vi who know English may have gone to the school, before it was closed. (Why was it closed? The Na'vi, or RDA?)
I know the story leaned this way on purpose, but the whole tone for RDA is "we want the rock, here's some shinies, get out of our way"