Do you really think the fact you found this solution to work means it would work just as well if everyone did it?

A self selecting group of people willing to build their own places taking on their own risks is not a good model for ‘what would happen if we got rid of building and fire codes?’

People who aren’t willing or able to figure out how to build their own house to an adequate safety standard are going to need to rely on being able to do things like buying a house someone else built. Inspection codes protect those people.

And when you factor in people wanting to live in denser groupings like in a town or city… well, how many times did San Francisco burn down before they figured out fire codes?