Yes it is quite true why a designer will host two different chips and going on switching applications between both of them, instead multiple cores will be better option, the power concern can be handled by turning on and off the cores dynamically.
Tools vendors will have their hands full with all the derivative cores. MIPS did this a while back with incompatible cores. As it is, every six months there is another ARM core, with their CMIS standards etc. If one A15 and one A7 core is run in the above diagram, the cache split will be interesting, and what about tracing this lot? How does the core decide what load to run? Surely the developer has to specify this. The comparisons of different cores at 45 and 28nm is misleading. Will be interesting to see how this takes off against NVidia, iMX6000 and other multi-core vendors with identical cores.
Not saying how important of the numbers of multi-core technology, ARM still has long way to go to deploy superior multi-core solution, like efficiency of ACP to improve I/O performance and Virtualization ...etc. Compare to ARM, MIPs IP price is far cheaper but eCosystem and power efficiency are also weak.
I've seem lots of me-too product with ARM solution in the market for specific regions, especially, China, Taiwan and Indian deploy similar Network and Media SoC in the market. That says, ARM is the winner of IP biz and leave the product competition to the chip design house.
For power efficiency, ARM do the best. It is its key competition. In China, more and more companies start to use ARM architecture IC with embedded Linux to develop products. The ARM core IC has the most large share market in China. It is also my first choice to make the new project.
Add in a graphics co-processor and you have little, big, bigger. It's an interesting approach and does make sense. With the graphics co-processor architecture, high-power functions are offloaded from the main processor. With this approach, low-power functions are off loaded from the main processor.
My understanding is that for identical cores On a chip ARM does offer a slight discount...this would drive down the royalty rate per core if ARM was not able to drive up the base rate!
ARM can try and do that by arguing that newer cores have increased functionality, performance. licensees can resist by saying that too higher royalty rate will make them look elsewhere!