MH only sells 3-4 million in JP, SW is not going to change that.
MH on Nintendo sold 1-2 million overseas while MHW on PS4/PC sold 12 million+ overseas. Cost means very little when one PS4/PC game outsells every single 3DS game across 7 years in just 2 years: return on investment is so much bigger with MHW.
The idea that the old model is more profitable is factually wrong. Capcom broke their FY records with MHW.
PS4/PC simply have a bigger audience for MH than SW ever will.
Some of you say you want Capcom to do a spinoff for SW. Again, not the best route, as a spinoff on PS4/PC/PS5 would sell multiple times better than a SW game.
You're failing to account for the fact that MHW opened up the franchise. MHW didn't sell way more than the series had before because it was on PS4/PC and not on Switch, it opened up sales so much because they made gameplay choices that appealed to more people. If it was on the Switch it woulda have destroyed sales of the series as well. It's not a PS4/PC thing. You can't compare old MH games to MHW and then say see it wouldn't have sold on Nintendo. That's like comparing BotW to old Zelda games and claiming previous Nintendo systems just didn't have an audience for Zelda but the audience changed for Switch. It is just plain wrong. The game changed to bring in more people.
If say MHW had come out on Switch instead you'd have 4-5 million sales in Japan alone, plus the expanded western audience due to the additional appeal the game brought in to the series. The western sales wouldn't be as large as they are now probably because yeah the PS4 audience is like built entirely on Fifa, GTA, CoD, and other action games, but the Japan sales would make up for that. Hell it might have even totally thrived in the West on the Switch as much as it has on PS4 because it'd be the only brand new AAA action game on the Switch outside of Nintendo properties.
The point is, they are throwing money away by not making the game for Switch as well, considering that Switch owns Japan and is the hottest selling system worldwide in a decade and we know that even 5 or 10 year old AAA games sell decently on Switch just from people who never played the games back when they came out or deciding to play it again because they can play it portable.
I'm not saying Capcom should abandon Sony/PC and do a Switch exclusive, I'm saying they'd sell many millions more copies of the same game if they spent probably less than 50% more time/money/effort to make a Switch version from the ground up. Unless Capcom is terribly limited in manpower there's no reason not to simply make another cheaper version of a mega selling game that would bring in millions more sales.
I do agree a spinoff isn't a good idea. Nobody wants a spinoff as some cheap consolidation - those are the types of third party games that do fail as one would expect them to on any system. Because there is no reason to not bring the full game built for the Switch to the hottest system on the planet that completely owns the market where MH has always been hugely popular.
Your logic is fundamentally flawed as you assume two factors are mutually exclusive when they are not. MHW allowed such an expansion directly due to it being on PS4 hardware that allowed a more open design, better graphics, animations and AI, all of which attracted new players into the series.
Not to mention the PS4 is ripe with a userbase that loves JP games, actions games and RPGs (FF, KH, Souls, Nier).
MHW's success is directly tied to PS4 (and later PC). SW only owns JP hardware sales, PS4 still sells a lot of software in JP. More importantly, PS4 owns WW. PSN has 113 million monthly active users, 44 million online subscribers and is far more lucrative to third parties than SW will ever be.
You keep quoting numbers that are baseless. I don't know how to respond to that other than they are baseless.
The reality of gamedev is you have a software pipeline. Said pipeline is a combination of in house devs, in house dev tools, outsourcing devs, infrastructure and talent acquisition. This takes 5-10 years to solidify to the point of efficient output.
SW is too weak to be considered in this pipeline, its Nintendo's own fault. Capcom would have to go out of their way to retune their in house engine and spend in house devs on SW ports of old software, which would have a lower ROI than spending those devs to work on new PS4/5 games. Lets not forget that they need to retool their engine for PS5 as well, a platform their entire output depends on.
TLDR: No one is ignoring the SW. Due to its low power SW dev is in direct competition with PS4 dev and PS4 dev is far more important to Japanese third parties. If SW was close to PS4 in power it would easily get those ports just like XB1 does or low end PCs.