You pay $1000 a month. Of that, $800 goes towards mortgage, far less because it is no longer a speculative investment.
It is bizarre that you think that housing is used as a “speculative” investment. Housing and stocks were monetized because our money is centrally planned and devalues through excessive money creation, and people simply need a place where they can store wealth without having it destroyed. If people could use money to store their wealth housing would be demonetized and prices would go down, then your coop model could naturally outcompete renting if it truly is superior. Fix the money, fix the world.