Even if they hit 15 mill this fiscal year, which may or may not happen, it's not like they are likely to be able to maintain that for the following fiscal year. Sales for the Switch would be like what? 10-12 million the following fiscal year (no Zelda, no Mario movie in 2024)? It's pretty likely Switch 2 is 2024 as selling that range (sub 15 million) is somewhere Nintendo likely doesn't want to stay in and with only one hardware product line it isn't like the old days where like "well OK the Game Boy and SNES sales are slowing but we've got the N64 coming out to boost overall hardware sales".
I can’t imagine many people are expecting anything other than a 2024 release at this point.
2023 seems off the table, there’s just no way they would forecast 15m if a successor was coming this fall and like you said, a 2025 release would be letting Switch sales get too low for comfort.
I think fall 2024 is when it will release, this gives Switch one more holiday all to itself and I assume they have a big Mario game coming (Nintendo would be stupid not to have a new Mario game to take advantage of the Mario Movie hype).
Announce Switch 2 around this time next year with a teaser trailer then around September have a presentation that goes over launch date, price, launch window titles, etc. and release it in November.
I think so basically, though I think they will announce Switch 2 more likely around March 2024 but otherwise yeah I would agree with what you're saying give or take maybe a month of two. I really prefer September launches anyway, it's much nicer weather and not having to lineup in the middle of the Christmas gong show shopping season is so much nicer too, I'd like to see Nintendo return to that.
The moment we saw Zelda be a May 2023 game was the moment we knew there was no new hardware for 2023 happening, because if there was then they almost certainly would have shuffled Zelda around a few months to launch alongside that. So the whole 2023 debate has kinda become anti-climactic.
I don't think really what the Switch does this fiscal year really impacts anything long term. Nintendo already I think has made up their decision on when Switch 2 launches and they've made that decision a while ago, this isn't like Nintendo is hanging on the edge of their seats and if Switch hits 15.1 million, Switch 2 doesn't get released in 2024, or if it hits 14.2 million Nintendo just dumps the Switch, lol. Like this transitionary time line is already well into place and where you will see it already is probably in the Switch's library lineup in the next 12 months, it may not be as heavy hitting because some, if not a majority of dev resources have to go to the new system.
Probably I would say the more pertinent actual question is how does Nintendo treat the Switch after Switch 2 has been announced. With the 3DS, the 3DS was allowed to hang around and sell for a few more years and get a few more big releases. With the DS, Nintendo choked DS shipments almost immediately to a trickle. This is actually probably why you want the Switch 2 to have a strong launch and a strong early sales cycle in 2024 ... because if there are hiccups, odds are Nintendo will go into panic mode and cut Switch shipments off sooner rather than later like they did the DS/3DS to force migration over to Switch 2. If the Switch 2 sells well out of the gate to higher end (possibly $399.99 range) early adopters ... then Nintendo probably is more relaxed and more apt to let the Switch 1 serve as a lower cost option for a few years like they did with the 3DS.