I expect at least a ~30% decline on total console sales this generation.
Last generation saw ~260 million consoles sold
This generation I would venture have ~180 million consoles sold total
The odds of two consoles breaking 100 million mark in a generation is hard to believe. My predictions now base don a 6-7 year life cycle?
PlayStation 4 - 90-100 million
Xbox One - 50-60 million
Wii U - 30-35million
Total - 170-195 million
I would love to be wrong and see consoles sell like hotcakes for years to come.