Sadly, that's at least partially true. But rebuilding on a sight where a home was destroyed eliminates the information value (that this site isn't safe from tsunami) and the coverage is far from uniform/regular (so you can't tell if there are no buildings in an area because it was previously undeveloped or is unsafe).
Japan has a bad habit of considering buildings as disposable. Odd that a land with 1000 year old temples knocks down 40 year old houses with zero remorse, but that seems to be the case.
