A little late, but your overblown condescension drove me to reply.
I don't know how many rural third-world self-built houses *you've* seen, but I've seen my fair share. Apparently in different areas than you have. Of course, most looked nothing like you described because not everything is done the same way as it is in whatever (likely singular) culture you've observed it in.
You can't simply reject efforts out of hand because they wouldn't immediately work in the situation you are familiar with. Other situations exist, and situations can drastically once that change is enabled. Of course, I don't see what your descriptions have to do with refuting my points. Not every poor society chooses to build illegally in the middle of town. Cheaper building methods benefit the poor who are trying to build shelter, regardless of how or where they do it.
The price WILL come down, regardless of what petty dismal you make. Even a rudimentary understanding of economics or the history of prices of nearly any manufactured item or manufacturing method is a pretty good clue for this. They spent a larger amount of money than they wanted to build a cheap house. That amount is still smaller than what many impoverished people build houses for. That amount will come down in time as the processes become refined and they are made cheaper by economies of scale.