I was thinking, since all PS4 and Xbone games will (also) be available digitally (Xbone physical games having pretty much no difference with their digital counterparts), tracking videogame sales of retail copies becomes a rather incomplete endeavor to the point of (almost) becoming irrelevant. Purchase of digital games will keep increasing. I would speculate the retail-digital split for Xbone games would be about 60%-40% at its peak, PS4 certainly lower but it will also grow in popularity. By the end of next gen I could see digital purchases being on par with retail sales across both platforms.
Retail trackers like the NPD, GFK Chart-track and VGchartz among many others will start to see their numbers become irrelevant as this generation progresses, and I doubt they will be of much use for software tracking by the end of it.
