It's exceptionally rare for one company to buy a whole IP from another. W101 is an extremely odd case that only came about because of how important it was to Kamiya while simultaneously being the biggest flop of all time and completely worthless to Nintendo.Nothing stops these companies or Plstinum to mske a deal to do a sequel for one of these or even buy the rights with all the tencent money.
And I definitely agree they could still partner with other studios in the future, but these were all announcements related to self-published games.