You're jumping to conclusions when you say "the only company who might pay for information is Nintendo."
Nintendo has yet to reveal anything regarding their new product. There are loads of parties vested in Nintendo, including retailers, publishers who are considering the NX but have not yet committed to Nintendo, and institutional corporate investors, who might be interested in how the market responds to various price points and product features. It could very well be that someone other than Nintendo commissioned it.
I have a hard time believing that it was Nintendo because this data would have been useful to Nintendo two years ago, not right now as the Nintendo NX finalizes production with a lot of the key hardware components already set in stone. Presuming they're releasing in Holiday 2016, it's too late to change the fundamental hardware decisions that went into the Nintendo NX. Even if the NX is coming out in 2017, it's still stretching it.
A more likely story is that some other client wanted to test the U.S. market in response to specific price points and hardware features so when Nintendo does make a move they have an idea of how the market would respond or how the general public might react to such news.
Alternatively, there could be multiple clients interested in such data. I wouldn't put it past the GfK Group and their >10,000 employees to commission a detailed study and sell it to multiple organizations as they have done in the past for other video game-related studies.
