One of the major problems with using the Infoscout data is that its scope is to limited. What I mean by that is the questions asked skew the data in a way that cannot be determined unless there was a more broader subject discussed.
Case in point, if someone asked me did I purchase my X1 for my kids, I would say yes. If that person also asked did I purchase the X1 for myself I would also say yes. As a family man, I have multiple motivations when purchasing a product. As for the X1 it fit nicely as something I could buy at a price point the wife would not complain, that the kids will enjoy. It also has a price that allow me to purchase multiple gamepads which is another expense and still be under the price of the PS4.
The key is that stating the PS4 is the grownup console cannot be extrapolated from the data using infoscout results. The whole basis of the OP relies on the theory that sales of the X1 increase because of family purchase for kids but that theory has way to many wholes to come to a reliable conclusion.
The one main constant that can be used is price. If you are a parent and you are looking for a home console system that pleases everyone, price makes a big determination before anything else.