The Victorian Era cities were a good approximation of hell. As for "moar density" bullshit, no large city in the US, Western Europe, or Japan lowered down housing prices by increasing density. But sure, we just need to allow real estate developers run rampant. Just trust me, bro.
As a practical example: Vancouver, BC rapidly built out fully automated grade-separated transit system. It then allowed unlimited density near transit stations (resulting in nauseatingly ugly high-rises), it (effectively) banned purely investment foreign purchases. Basically, it did all the wishlist of misery pushers.
Can you guess the outcome? Hint: it's not "affordable housing for everyone".