I guarantee you MS wasn't looking at how the 360 was doing and growing and thinking, "Darn, we're not 'winning' AKA beating the Wii."
Oh no, they surely as hell were looking at the 360 vs the Wii.
That's why we got Kinect from them (and Move from Sony)
That... doesn't really change that the mobile market is doing great.
Of course it is, I'm not claiming otherwise.
Let's try to add a couple of definitions so we have a complete picture.
Oldgen, for me, is PS3/X360/Wii/DS/PSP
Currentgen is PS4/XB1/WiiU/3DS/Vita
I think we should not include mobile in the comparison because mobile basically didn't exist back when the oldgen started: it appeared during the previous generation, but I think it actually affected the current one, not the previous (as DS+PSP sold over 200 million units and 3DS+Vita will likely fail to even reach half that number)
Mobile is also a completely different business model, for good or worse, and that's what makes the comparison even more difficult.
But most of all, you original claim was about the console market: we do both agree mobile is a totally different market, right?
On the other hand, we still have consoles and handhelds, with most of sales coming from physical (but strong rise of digital, that has to be acknowledged) and extra sources of revenue that came to life exactly during the PS360 era (DLC, microtransactions, paid online)
So there *is* a 1:1 comparison that we can make. Hell, current gen even has Nintendo fully onboard with all of this if we choose to include the Switch (it's just partly onboard if we only consider the WiiU due to its free online)
Now, we have less hardware being sold and less software being made for the platforms listed above... It could be a healthy market (depending on who you ask) but there's undoubtely a decline, if you ask me.