I think there is probably a bit of market contraction although certainly NPD is missing an increasing portion of the market with digital sales across Xbox Live and PSN whether it be games, points, or subscription revenue. We get some of that in the earning reports for companies but even with NPD estimating that stuff for separate reports its probably not reported in the very broad stuff they release.
Tablets, ios, android, smartphones, facebook are markets that didn't exist just a couple of years ago. More people are gaming. They just do it across more platforms at the moment. Certainly some of that is new gamers and some of that is siphoned from the existing markets like consoles.
The other bit is that Wii sort of over-inflated the market. Now that's its dead you are getting some poor year on year comparisons as the bubble broke.
In general though I would say there is nothing to worry about. Consoles are doing fine as long as they adapt to the changing market.