While most of those comments are reasonable you really wouldn't be saying that the historical average for Mining Capex was at the year 2000 levels would you? That was the dot com boom and bust with record low oil and metal prices. You may as well say that 1929 was an average year on the stock market!
You are right of course that most markets, and particularly commodity prices and exchange rates, always 'over shoot' on the up and on the down sides. I remember everyone laughing at Pierre Lassonde when he predicted a future gold price of US$2000/Oz in 2002 (I think it may have been?), from 1997 to about 2003 gold was clanking around the US$300/Oz cellar and most economist were writing its obiturary. The laughing definitely stopped once the GFC took hold and the price of gold kept going up.