Erm. I'm not sure the part about the dwindling number of pegged currencies is true, but I'm too tired to do the research tonight. Nixon closing the international gold window certainly did happen, but it was probably caused by, rather than causing, inflation.
Currencies are highly fungible. The dollar is shitty, but it still beats all of the alternatives. Any country could swap their dollars for any other currency, more or less at any time. So we must come to the conclusion that countries keep (and accumulate!) dollars as reserves because they prefer it.
Yep he stopped the gold standard because of inflation and he knew investors
would start were raping the US' stores of gold in exchange for dollars
which would have crashed. So he decided to let it float, inflation exploded after that but maybe not as much as it would have if the foreign investors cashed out.
Fixed that for ya. The closing of the gold window was Nixon's solution to the
Triffin dilemma. Well, maybe not solution exactly, but at least an attempt.
The era after the close of the international gold window is known as Bretton Woods II, or the Washington Consensus.