Well, I'm sorry to say it, but it seems like chip makers were all "poweerrrrrr, ahhhhhhhh," but they ignored the real world ramifications of such desires.
Qualcomm and MediaTek have been looking into the developing of eight-core (octa-core) processors explicitly for use in smartphones, that much we know. As it would turn out, their plans have been put on hold according to a product roadmap revealed at MWC. When you think long and hard about the news though, it makes a lot of sense.
The current iteration of mobile operating systems is specifically optimized for quad-core chipsets. The very first Octa-core processors to launch probably would not be utilized by the OS well anyway, at least not until the software is modified to do so. That being said, it's genuinely hard to guess what an eight-core processor would provide for added performance, if any at all.
Industry sources mention that software compatibility, and consumer demand are the real issues when it comes to eight-core CPU development. Most phones arriving on the market are currently running a dual-core or quad-core processor, which means consumers will be locked in for another two years with a quad-core phone, at the most. Sure, some of us certainly love the idea of an octa-core smartphone, but not everyone can justify the cost either.
MediaTek admitted that there is no meaningful demand for an eight-core device from its "clients." Instead, the company will shift its focus to work on optimizing current generation hardware.
Just because, MediaTek and Qualcomm have suspended development, doesn't mean that other companies will. Samsung and Huawei, for example, are still working diligently on an eight-core smartphone. Samsung's eight-core Exynos 5 Octa will probably be included in the upcoming Galaxy SIV and Galaxy Note III. Keep in mind, the US Galaxy S IV model will be outfitted with a Snapdragon 600 CPU instead of the Exynos 5 Octa.
Unfortunately, we'll have to wait for a little while longer to find out if an eight-core CPU actually does improve smartphone performance. An eight-core processor will definitely be useful, and more powerful, when the software is optimized appropriately. Right now though, a significant performance gain is uncertain.