Maybe import laws are a factor, but most likely they haven't entered Brazil because the local competition [1] wouldn't make it profitable.
Besides crazy import laws, what I see as the major blocker there is that Brazilians are not very fond of self-service stores and of having to carry their purchased stuff home and assemble it themselves.
Of course IKEA could try what they do in places like China, where they partner with a local company for delivery/assemble. But then maybe the price for that service would be a factor.