That's not always true. A modern brick home is wood-framed with a brick face, but many older homes in Canadian cities are actually brick and beam construction. Walls are all double brick with wooden beams for floor joists that insert into the first layer of brick and sit flush to the second layer. The exterior structure is all brick, and brick is literally holding up the floors and roof. You can't really compare a timber house with a brick facade to an actual brick house. And yes, most people living in brick-face houses don't seem to realize they aren't brick houses. I can't explain that part other than ignorance.