That's exactly the point. Gold maintains its purchasing power over time. Fiat currencies do not.
Did you forget my post?
If you buy anything else, let's say a house, then gold isn't as good. In 1980 the median house was about $71,000 (about 90 ounces of gold) in 2005 the median house was about $253,000 (about 500 ounces of gold)
Gold hasn't maintained its purchasing power since 1980.
Fiat currencies do not.
If you can find where I said they did, you can slap me like I slapped lurker.