What is the evidence you have seen that means you can categorically rule this scenario out? I've been looking, and I can't see anything. Therefore, what makes my scenario (based on the lack of knowledge on immunisation, the lack of a vaccine, the inability to test enough of the population of practically every country) more unhelpful than the scenario that life will be back to normal in time for Christmas. I have not said anywhere that this WILL happen.
The Spanish flu was with us for 2 years - this was exacerbated by people returning from war and malnourishment. It died a natural way, but at a time when people weren't travelling all 4 corners of the globe. How easy do you think it will be to contain a second wave that originates in America or Australia or India?