The latter is because they finally got the hardware down to manageable costs. Now imagine manageable hardware costs through most of the generation.
I'm not talking about this generation specifically. In general, it's always in platform holders' best interest to keep the same hardware as long as possible, whether it's profitable out of the gate or only in a later part of its life cycle. Of course, someone will always make the move first, to set its product apart, and others will follow, but ideally longer generations mean making money longer, without the need for large investments in generational transitions.
I think you're take that from the perspective of what we saw this gen.
No, it's the same with every transition, games become more expensive to produce. It was the same going from PS1 to PS2, it will be the same going from PS3 to PS4. Content creation is the biggest problem, not programming - the tools and artists that use them just can't keep up with the demands set before them by better engines asking for more and more detail, better animations, more content and so on.
As a side note, the last transition saw the target resolution go up from 640x480 to (ideally) 1280x720. That's a factor of 3. This one will see the target go up to 1920x1080, a factor of 2,3. Not a huge difference.
If the rumors are true, I think kinect + a more ergonomic WiiU-esque tablet controller would be the perfect solution. Casual games could just use the touch screen, whereas hardcore games could make the most of the features of kinect without sacrificing complex gameplay.
No tablet controllers, please. If I want to use a tablet, I'll use a tablet.