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.
And you are heavily cherry picking when it comes to japanese third parties. Playstation has been losing many previously exclusive Devs and Publishers over the past few years.
The japanese market is more than Capcom.