I believe the word you are looking for is "imagination" instead of "fantasy". (I am just saying this, because I am aware that English is not your first language.) The overall point of your first two paragraphs is, "Looking at past history is important, but under unusual circumstances imagination is also very important."
I also agree with the point of your last paragraph. The main problem with the conclusions of @Shadow1980 is that he is ignoring the magnitude to which the Switch is up YoY. People who study a lot of data are actually the most susceptible to confirmation bias, because we all naturally tend to focus on the data which reinforces what we already believe. It can happen to the best of us. Normally the way to get around this is to make a prediction. If your prediction is right, then your explanation becomes stronger. If your prediction is wrong, then you are supposed to change your beliefs about what is happening. Here is what happened with Shadow1980.
He predicted, "PS4, XB1 and NSW will all be down YoY in 2020." Here is what the data (worldwide) is currently saying:
His prediction was right about PS4, wrong about XB1 and massively wrong about Switch. COVID alone would be enough to explain why XB1 is up YoY, but that isn't sufficient to explain the Switch's massive growth. He wants to explain everything away with COVID, because he wants to stick to all of his current assumptions about how the video game market works. That is confirmation bias. He also tends to only use US data only, and the US just happens to be where the effects of COVID are the largest and longest lasting. That further fuels his confirmation bias. NPD data isn't even that reliable anymore, because it all comes from leaks at this point, but he insists on using US data.
Now I do agree with Shadow1980 on one thing. Animal Crossing alone doesn't explain the Switch's massive growth. However, the idea that COVID alone expains the Switch's sales is an even worse explanation. There is actually more going on here than COVID+Animal Crossing, but Shadow's explanation is that it is less going on. He thinks it's COVID alone.