I really wish people who aren't engineers or software developers or IT technicians would just stop talking about iOS technical capabilities versus OSX because you have no idea what this technology actually is and you're just throwing out words like "mobile" and "desktop".
No, you can't just get iOS to perform x86 instructions. At all. Ever. They will not work in a box. They will not work with a fox. They will not work in a house. They will not work with a mouse.
I especially like people saying that an iPad Pro with some frankenstein desktop iOS would be faster than a MacBook. News flash, no it will not. And you should stop talking about this because you don't know what you're talking about.
You can not simply "add desktop" features to an OS. You have to completely rebuild the OS from the ground up because x86 instructions don't stay the same every year. ARM is not CISC, it's reduced instruction set computing for power efficiency. You might think, "Oh that just means it's better because it's more efficient." No, that means it was engineered inferior on purpose because its primary use is efficiency first, performance second.
This is why Geekbench scores are irrelevant comparing the Core M in a MacBook to an iPad Pro. While I am very disappointed in the MacBook's Core M, I won't make the same mistake a lot of you do by thinking that just because it's faster in iOS, it's faster period.
If you were to load a CISC based x86-64 operating system to an iPad, it would run like molasses because it's not built for the thousands of different instruction sets and the inability to perform "load and store" register logic. Basically, instead of storing instructions from memory into the processor registers so the processor can handle the parallel computing by its own sorting methods, an ARM processor attempts to compute "instruction per clock cycle" as it receives them, which creates a huge bottle neck on x86-64 instructions. CISC processors have hardware built logic to handle this type of instruction loading.
It would take 5-7 years to build iOS to handle those types of loads and it would immediately make any devices prior to the change completely unusable on the same OS. Also, the iPad itself would have to use an x86-64 processor, meaning the ARM that it's been building and researching would have to completely change from ARM instructions to x86-64 CISC.
The question remains: why can you run iOS on a laptop computer but not the other way around? Because RISC is software based and software dependent.
Please educate yourselves and never speak of this again until you actually know the science behind it:
http://cs.stanford.edu/people/eroberts/courses/soco/projects/risc/risccisc/
http://stackoverflow.com/questions/14794460/how-does-the-arm-architecture-differ-from-x86