I've been playing SC4 on and off for a few years now and I keep running into this problem... As my city grows to around 100k in pop, my RCI demand for res stays relatively close to 0 for R$$ and R$$$ but is pretty close to maxing out at R$. I try my best to build neighborhoods for low-wealth res, but when demand for higher wealth res increases, my low-wealth upgrades to higher wealth, which then leaves me with the same problem as before. I understand that if you build neighborhoods with no resources (health, education, water, etc.) it'll stay low wealth, but without these I can't build high-density low-wealth buildings. So basically my question is, how do you build high-density low-wealth neighborhoods and make them STAY low wealth?