Honestly MH coming to Switch was pretty obvious, even without the leaks. All you had to do was look at the credits of World and Iceborne and take note of the lack of Yasunori Ichinose and multiple lead designers from the portable/X series(Katsuya Eguchi, Yuji Matsumoto, mori-bite). Unless they all decided to leave Capcom and ignore the success of the 3DS games and the sales of the Switch, they had to be working on SOME kind of MH. Sure, they COULD have been working on a PS4/XB1 game, but Iceborne coming out late into 2019 and being supported throughout 2020 (along with no leaks hinting towards another MH on current gen) should have been a big hint.
People thought that because Capcom hadn't put out RE7/2R/3R or DMCV that they would never give any meaningful support to the Switch. Whereas if you had any knowledge of Capcom's dev teams and the series' history, you would know something was cooking for Switch.