TheoTown

my population 6900 but all habitants poor, not middle, not rich. why?

Middle class and rich habitants will only move in if there is available $$ and $$$ housing respectively. To create a demand for better housing, you need to build schools primarily, but I think as your businesses and industry level up they generate demand for better housing as well. Also remember that next level housing (high rises and stuff) require a 2×2 space.

You need a primary school for §§ and a high-school for §§§
In addition a hospital should help.

Signature says it all.