PS4 is a cash cow for Sony - that's the biggest advantage it has over PS3. 95m-125m is what I'd go with personally, and a lot has to go wrong for it to be at only 95m. Sony had no reason to keep PS3 around once the PS4 was up and running profitably.
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu