You're assuming the people affected did some kind of rational cost/benefit analysis, and just whatever choice they made was worth the chance of people dying. I

You're assuming the people affected did some kind of rational cost/benefit analysis, and just whatever choice they made was worth the chance of people dying. I very much doubt that was the case. You also seem to be falsely assuming there's only three options: be rich, live in a death trap, or be homeless on the street. That's not the case. People can be tricked, be stupid, just have bad ideas, or similar. Building codes are a check against all that. And if they make a certain class of housing more expensive, there are always alternatives of other classes of housing.