Your comment doesn’t make sense. What does diversification have to do with the net loss?
The USA is the largest producer of oil. It is a net exporter. From a pure economic basis alone, cheap oil is a net loss to the USA.
This, of course, ignores the strategic importance of the USA being energy independent—Trump can ignore the mullahs or bomb them, and they don’t have the weapon of an oil embargo. They have no power.
Much the same with Russia.
China, the largest importer of oil, however can fuel its economy cheaply. It even imports natural gas (which yes is almost free).
The end result of letting this go on will be dependence on the mullahs. Jimmy Carter malaise times.
What is Irans primary source of revenue? Petroleum products?
The US does produce energy but still have some manufacturing, R&D, consumer products,...