To be honest the Japanese have it right. Tear down buildings after 50 years and build something new. Ofcourse they had the luck of frequent earthquakes and fires (buildings made of wood when the Netherlands switched to masonry in the 16th century).
Yes it is cute and adorable that the Dutch Parlement is situated in a building complex that can be traced back 1000 years (I wish I was kidding). The tourists love it. The symbolism is marvelous. And it costs hundreds of millions to keep it from falling down.