When Brenton Woods collapsed oil was at $3.56 a barrel, so your perfect correlation is lost. As for your understanding of Brenton Woods, it's also lacking. Fiat currencies could be converted into the Gold Backed dollar, and the dollar could be exchanged for gold at the "gold window". In August 1971 Nixon closed the gold window to eliminate the arbitrage opportunity, because, lets face it, $35.00 were not worth an ounce of gold at the time. As for changes in values of currencies, fiat or otherwise, that was Economist speak in terms of "constant dollars" and "purchasing power parity" to deal with these differences. As for FDR's gold grab, most of it was turned in at 20.67 an ounce. Over half of the 1.22 billion in gold outstanding was in certificate form. After the cut off date, 287 million in coin remained unaccounted for, indicating almost 80% was actually turned in. (Friedman, A Monetary History of the United States 1865-1960, 9th paperback edition, footnotes page 463-464.)
The relationship you express between Gold and Oil is nothing new. The Saudi's for along time have at some level unofficially thought of their price targets for oil in terms of gold. We can also see this in the econometric model I posted earlier where X(1) is the CRB commodities index. This index is heavily weighted to the price of oil.
As for Fiat currencies ALWAYS being devalued, let me as you this. HOW MUCH OF YOUR WEALTH IS ACTUALLY IN DOLLARS? If you were to look at the personal balance sheet of most americans, our assets are not in dollars. Sure you may have a few months worth of expenses in a plain savings account, but most of your assets are in equities, real-estate, bonds, and other real property such as pianos, antiques, guns and ammo. Some will have a position in precious metals, and may even have a position in foreign currencies.
As for what's considered currency during a true EOTW collapse, look at the Chinese famine of 1941. By and large, those most affected by the famine did not accept precious metals for barter, the two mediums of exchange quickly became gain and daughters.
If you are truly worried about a collapse, you might want to put aside a few Koku of rice (the Koku is an ancient Japanese currency equal to the amount of rice required to feed a man for a year), and have a few daughters.
One of the benefits of our current system is it allows the American participants the freedom to own a diversified set of assets to hedge the impacts of inflation, or for some profit from them.
As for what will our currency look like in 2500 years?
I suspect with will be virtually all digital, or we will be back to gain and daughters.
As for your predicted collapse, when do you expect it to happen?
