Actually you'd need to get oil to stop being denominated in dollars, Russia to have an economy that was more that 2% of the world's GDP, China to cut off the 25% of their exports that go to the U.S. and be willing to write off most of the trillion in USD denominated US debt they hold (Trump's working on that), get everyone else in the world to agree on a replacement common currency, rewrite every contract, precedent, and process that is dependent on the stability of the dollar as a reserve currency, and about a thousand other things for the "dollar to collapse".
And seriously, Gaddafi and Saddam were killed because they were a threat to the U.S. dollar as a reserve currency, get a grip man (also helps your credibility as an expert on what they did if you know how to spell their names)!