You're not wrong, but the fact is that it's actually really hard for tenants to even enforce existing laws, and shitty landlords know it. You need to pay to file your lawsuit, you need to know the law down pat, you really need a lawyer (that you often can't afford because they're all on retainer for the big landlords), and even if you ask the local Department of Health and Human Services for assistance or whatever, you'll be on a waiting list for MONTHS because there's probably also a hundred and a half other people who are trying to do the same thing against their shitty landlord. The people that this system benefits know how much of a pain it is, know how long you'll realistically take to get anything rolling, and know that if they give you a short enough timespan, you're going to shrug and say "well OK then" more often than not.