I don’t know, but the people saying there’s no chance aren’t to be respected. The momentum is currently very high, and it’s not likely Nintendo will cut support any time soon, especially with continuing third party support like they have traditionally done from SNES onward - a stupid strategy IMO, but there is a chance they’re done with it.
Support or not, the successor will be a factor. There are a number of factors, such as whether or not the next generation of Switch will be considered separate or part of the Switch family of consoles like GBC was to GB, DSi was to DS. Nintendo has experimented with longevity in the 3DS, although on a much smaller scale. They also continued running it alongside the Switch for a bit longer.
Of course, iterative or not, if the next Switch is represented as a completely separate system, then it will probably come short simply because of the cannibalization factor.
I do favour higher sales at this point. Someone with more darts than I’m willing to dig up can verify that even with a steep decline curve, the Switch will at least hit third place. But a steep decline curse would require Nintendo actively transitioning away.
I describe myself as a little dose of toxic masculinity.
