Earthquake proofing doesn't have to be that expensive unless you want to build massive skyscrapers. There are a lot of old, cheap buildings in Japan which have survived a long time despite predating any kind of modern earthquake-proof engineering.
The problem in Haiti seems to be the growth of unplanned urban slums which have been built hastily and to very low standards and in areas that aren't always well suited to building on. It's not hard to improve on that.
Here's an example of charity-built housing in Haiti.
It's not luxurious, but it will survive an earthquake pretty well due to the small size and ductility of the materials.
Like, the situation in Haiti sucks. It has always sucked and the international community shares a lot of responsibility for why it sucks so much, but at the end of the day it is just a matter of money and making sure money actually gets spent on the right things. The latter is hard in a country as fucked up as Haiti, but there's no reason to believe it's impossible.
