PS3 Developer Has Shifted 'Entire Focus' to PlayStation 4 - Report
I'd guess this confirms LESS than 2 years to a PS4 release. Normal development cycle for most games I've heard is 2 years. IF all are on the PS4 project that might indicate a need to push for a less that 2 year window.
The Digitimes article is getting more support.
Another guess would be it's 100% backwardly compatible with the PS3 and a game developed for the PS4 could also run on a PS3 with somewhat less game detail like the Vita does with PS3 titles but in reverse. Something like this would shift a developer to support the more powerful machine with down-converting resources to a PS3 possible but up-converting to a PS4 more difficult. You don't drop support for a platform (PS3) with millions of potential customers for one that is just starting, you support both unless my above reasoning is accurate. This would remove much of the support for PS4 early release but both guesses could be accurate.
More support for a Cell type CPU?
In reading through older threads on the PS4 some things pop out. Sony might use cheaper DDR ram and that would require more eDRAM in the Cell. For cost reasons Sony in the article is going to use the same SPUs with minor changes (more cache assumed) and a FEW more SPUs to be determined by developer feedback. They might use a couple of newer PowerPC CPUs in addition to more SPUs, I certainly hope so.
The article mentioned a 4 year life cycle for the Playstation not 10 years in future generations because creating a Playstation console with tech/power that lasts 10 years is prohibitively expensive. This supports a PS4 that is not 10 times more powerful but some lesser amount to be determined by both Game Developers and Sony...PS4 cost the determining factor.
Factors supporting an early release of a PS4:
1) DRM, the current PS3 is broken, a new Key and system is now more likely.
2) Power efficiency, third world countries are the next big market and cost of electricity is expensive. That can be partially fixed with a new smaller die size.
3) As Patsu said, a higher res PS Eye is needed/rumored but the current USB port couldn't handle that. That has new Set top boxes by others having a much better picture than Sony products. In my opinion a big plus for a new system.
4) Voice and motion detection using pattern masking recognition is very memory intensive, the Kinect method and "move" are shortcuts to use fewer resources. More memory is needed.
5) 3-D is just barely possible on the PS3 for AAA games and a slightly more powerful chipset needed. 1080P 3-D and higher framerates for 2-D needed.
I doubt this rumor (20 Million sold the first year) unless newer hardware is faster, uses less power, offers more features and is cheaper. The same theme is in all articles, cheaper with less than our wished for 10X increase in performance. This also would allow an early release for the PS4.