I see no danger of the US "collapsing" faster from Iran. The US is self-sufficient in oil, and if Iran does close the Strait of Hormuz and/or threatens Middle Eastern oil production for a prolonged period of time, it'll actually be the US's allies and rivals that suffer the most. The damage to India, Europe, Japan, etc. will be immense, and the US will be able to hold them hostage over the supply of oil from the American continent, which will become the main global pipeline, and just so happens to be under the US's "new Monroe Doctrine."
There is little those countries can do about this, since the US controls maritime access to the American continent, so the US will be able to dictate to them what they must pay and do - ie if the US wants Japan or Korea or Germany to build weapons for its war, they will hardly have a choice now that the US holds their economic life line. Desperate people are much better workers.
The only country that can kind of throw a wrench in this is Russia, if Russia orchestrates a grand bargain with the US's allies in Europe and/or Asia to get them out of the US's orbit. But that doesn't seem like something Russia can presently do and in any case, all of the countries I mentioned are so deeply tied to the US empire that they can hardly extricate themselves.
