So you quarantine against every possible epidemiological threat just in case one turns out to be pandemic-worthy? World economy grinds to a halt. Shipping stops. Contracts broken. WW3 breaks out due to non-delivery of goods. Then the hyper-preppers finally have something to do.
Don't be ridiculous. You quarantine only against those threats that are both contagious and have a high fatality rate. That pretty much eliminates your doomsday scenario.
And your doomsday scenario isn't even close. The world economy would not grid to a halt. Shipping wouldn't grind to a halt.
And even if all international trade suddenly halted, the economies would keep ticking along. There would be some shortages, and we would learn to substitute.