I live in an old (1896) house constructed with douglas fir and redwood that is thousands of years old and incredibly dense - it's hard to pound a nail into it. Today's houses are framed with wood that is very 'green', soft and flammable and cladding that is little more than thick cardboard with weathershield on one side.

It seems likely the next generations of materials will be even more ephemeral and designed for speed of construction...concrete seems to be the only material resistant to this, although older concrete is a lot more dense than the mixes we buy today....