The point is that portable gaming remains popular in Japan while the market share for non-portable gaming has fallen considerably. Switch figures can't be used to show that non-portable gaming is recovering because it can be used as a portable. The only way to use the numbers would be to know what the Switch would have hypothetically sold if it had no handheld/portable capabilities.
"By that logic, Nintendo would now be less popular in Japanese homes than they were with the Wii U." - I'm sure that in the alternate-reality where the Switch can only be used hooked up to a TV it would still be doing a lot better than the WiiU in Japan. But this isn't the type of comparison that I was trying to draw attention to lol.
"From a publisher perspective, Switch is really awesome. No more headache about the decision to make a game for a home platform or a portable console because both bases get covered with a single effort." - I agree.
If you wanted to rule out Switch from the beginning, then what was the point of your question to begin with? You know that you are left with only the PS5 and Scarlett then, and you are basically asking if they can sell more than 12m combined. That's akin to going into the NFL thread right now and asking if the Miami Dolphins can make the playoffs.
Eh, I'm not left with just PS5/Scarlett cause the question wasn't time limited lol, it could be the generation after that or the one after that. Though even if I was just asking for PS5+Scarlett, it's more about the marketshare I'm interested in (% sold in Japan) than the 12m figure.
With each generation the % of total sales coming from Japan has declined for dedicate home consoles (27%, 23%, 14%, 9%, 7.5%) Will this number recover, that's the question, or are consoles that need hooking up to a TV to use dead for good.