For normal social techs, we can have them grow normally, via the standard tech model only. Make applications like Republic or Libraries available as an option for the player to propose implementing. Use the gov/social model to determine whether the thing can be implemented.

That lets us test growth and effects now. Of course, it won't be complete since social conditions will have no effect on tech growth, but it lets us start.

I especially like the fact that we could handle breakthroughs like applications. At first I thought it was cute, but a kludge in that breakthroughs and applications are very different. But if you look at breakthroughs as a tool (like a rifle) whose purpose is to revolutionize some aspect of the game like tech (as opposed to warfare) then it seems to work fine.