I have not seen a rumor suggesting the Switch specs are responsible for Worlds not coming to Switch. I have on the other hand heard rumors that Sony came to some sort of agreement with Capcom in order to secure MH Worlds and keep it off the Switch. What does MH XX not currently slated to come west have to do with anything? Switch has been the number one selling console in Japan since it launched. It is still selling out. Splatoon 2 will help maintain that momentum for a long time. I doubt Capcom is going to shun the Switch with no further Monster Hunter games. Look at the games and look at the specs? That is very subjective, and can hardly be considered proof for your arguement. I do not personally see MH Worlds as being all that visually impressive, but that doesn't mean it is or isn't a technically demanding game. The eye test isn't great for determining just how demanding a game is.
Developers do as their told. If the upper management team decides they want a given game on a platform, the development team is tasked with the job. Developers of AAA titles will always prefer to have more capable hardware as it makes their job easier. COD was ported to Wii for years, and that was a much tougher port than anything from X1/PS4 to Switch. It comes down to return on investment. I think it is more likely that western publishers are skeptical their will be a large enough audience on the Switch for their games that will make porting their worth the investment. Follow the money, it usually makes things make sense real quickly. Ubisoft pitched Mario+Rabbids to Nintendo, not the other way around. Why? Because Ubisoft knows by using the Mario IP their game has a much better chance for success. If Ubisoft green lights a sequel to Child of Light, Switch will get a port. Child of Light sold well relative to other consoles on Wii U compared to Assassins Creed 3 and 4 that sold terrible relative to other consoles.