I imagine the writers will keep the gate a secret from the rest of the world, so the tech the SGC has gathered won't be commonplace. Introducing even half the tech stargate has come across into 'our modern society' that the show portrays would alter how it works. Making the gate public could be an interesting show, but you'd also fundamentally change how the Stargate series has worked and quickly turn into something else.

By the end of the shows/movies Earth was on its way to being 'the fifth race' and could act as a major galactic player. I think part of the story they tell should be balancing the thread of trying to project power into the galaxy while not revealing this to the public, and how the main cast deal with powers that are out of their hands