Sony will not go after ATI for a GPU when they have a great relationship with NVidia. Using a GPU like this is not only expensive, but also requires extra cost on PSU, Cooling and more. I think that both companies will stay with ATI and N-vidia respectively. Plus after the PS3 and 360 high costs and losses I doubt either of them will move to another CPU either. Microsoft paid a fortune to have Xbox games emulated, and Sony developes hated the Cell early on. Sony may move to a multicore Power PC based CPU if it can emulate the Cell processor in real time so they can make the PS$ backwards compatible, but..
One option they may take is to use several chips like the Tegra 4 for parallel processing. They are cheap, powerful for their size, Use little power, are scalable, and there are a zillion programmers for them. In some ways it would make sense for Sony to use something like these chips and steal away the 'Free Developers' from Android and IOS and let them make money on the PS$.
