Yours is just a theory of many. There's no evidence for anything you just said. At least I was basing my assumptions off history.
Wii had 6 years before WiiU came out. In case of Switch that would be March 2023. That's in 2 1/2 years. Certainly not within your 3-4 years estimation. On top of that I proved how badly the Wii sold in 2012, the year WiiU launched. Only 5 million sales. WiiU was announced 1 1/2 years before it came out. Using the same time spans, Switch 2 will be announced in Fall 2021. That means Switch would have only 12 months of strong sales left and then could drop off completely in 2022.
Btw. the successor to N64 was released after 5 years and the successor to Gamecube was released after 5 years. Finally, the successor to WiiU 4 1/2 years later. Yet you expect 6 1/2 years to 7 1/2 years for Switch.
No, what I said is looking at things from the current context. You're trying to compare a system that is about to possibly have a 30 million YEAR, to systems that sold 13 to like 33 million in their entire lifetimes! And you're also trying to compare it to a system that was crazy hot for 3 years and then declined hard and was relied on non-gamers to become a super hot seller. It is extremely easy to point out how your arguments are very flawed and make no sense in the context of the Switch. Call my reasonable and common sense arguments "just a theory of many" if you want, what I'm saying is pretty obvious and I'm at least talking about the Switch, while you're trying to compare the Switch to N64, GC, and WiiU lol!