you are wrong, Nintendo switch, until now, is severe supply problems. Lotteries anywhere. The sales are not in decline or become or same status to the pre-AC level. The sales is bigger than same period now, with supply problems.
The covid problem helps, but is not the mainline driver. Animal Crossing is.
The thing is, it will forever be impossible to know what the HW sales in the weeks immediately following AC's release would have been had the outbreak never been a thing. If there is suppressed demand, well, we should see some indication of that in sales data in the not-too-distant future when supply gets back to normal. Even then, it could be hard to say if it's simply just general demand that's been pent up, or it it's due to AC. But there is one thing we know absolutely for certain: Only one game ever in the history of the Japanese market—ONE, out of however many tens of thousands of console games released since Famitsu started tracking sales—has caused a boost to hardware sales lasting for more than two months, and it was for a system with already poor sales. There is absolutely no proof that AC could have been a long-term system-seller. It may have ended up being a bigger short-term system-seller. The data clearly shows that it had that potential, seeing that it produced the best non-holiday, non-launch week ever for any system in Japan. But its popularity as a game or its ability to move hardware in the short term doesn't guarantee that it would keep moving a large enough number of units for month after month to be noticeable in the data. Just because someone thinks it could doesn't mean it actually could.
It seems like some people are attributing near-mystical attributes to the Switch's ability to sell, and the ability of its games to boost its sales, and to just generally violate any and all historical precedent or other notions of how and why consoles sell what they do. Well, sorry, but it doesn't work that way. Extraordinary claims require extraordinary evidence, and in this case there is no way to produce evidence that AC would have been only the second game ever to be a long-term system-seller in Japan. It's just not possible with the available data. But every single bit of historical precedent indicates that AC would have only been a factor in the short term. The Switch is a great system with great games, but it still obeys the same "rules of sales" as every other system.
And in the U.S. the data shows that the COVID effect is the primary driver. I've already gone over that. If you have proof that AC is the primary driver in the recent spike in the U.S., well, let's see it. Otherwise, all you have is assertions, and assertions are not the same thing as facts. And since I'm not interested in arguments not backed by data, if you have none then we're done here.