It looks like a Buddy System is coming in "Pokemon Sun and Moon" soon as gamers discover files hidden in the files that is related having a buddy system in the game. Although no confirmation has been given yet from Nintendo, news claim that this feature is well-developed in the game but has not been used all throughout the game.
According to reports, there could be many reason why this feature has not been used in the game. One theory is that as developers work on each feature, some might not make it in the initial cut so its left in the game files untouched. But that doesn't mean that it will never be used in the future. There can be future updates activating the feature.
Another reason is maybe the game developers need more time to polish the files and prevent any glitches from happening when it is activated. So for the meantime, they have decided to keep it in the files. However, all of this is still speculations and remains to be unless addressed finally by Nintendo.
As to when will Nintendo plan to activate the feature, many believes it should be sometime soon after "Pokemon Sun and Moon" has launched the game in Nintendo Switch. Although this as well is still a rumor and has not been confirmed by the company, many expects this to happen soon. An expansion like this will certainly make the game much popular than it already is.
"Pokemon Sun and Moon" has just launched last month and so far it has sold over 10 million units in just 7 days and has become one of the bestselling games in the history of Nintendo. The game features a new generation of Pokemon including mythicals and legendaries that players can catch in the game and train as their own.