that is because people knew they could get a better version on PS4 and those who has a last gen console didn't see the point of upgrading to a Wii U as there was no significant benefit.
Atually, some of those games aren't on PS4 (AC3, Batman Arkham City, Black Ops 2, etc).
But I get what you are saying. Thing is, that the same thing might probably happen to the NX since for those people that already own a PS4 or XBone there might be no significant benefit.
“Simple minds have always confused great honesty with great rudeness.” - Sherlock Holmes, Elementary (2013).
"Did you guys expected some actual rational fact-based reasoning? ...you should already know I'm all about BS and fraudulence." - FunFan, VGchartz (2016)