ARM and x86/x64

I'm just wondering if ARM's performance come close to the "non-atom" x86 chips. I know they have different instruction sets, yadda yadda yadda but with the coming of Windows 8/RT and the newly announced Samsung Chromebook with a Cortex A15 processor, I'm beginning to think that x86 will be replaced in the veryyyyy far future. Also, I read somewhere that PowerPC has a different instruction set but is traded away by Jobs with his decision to switch to Intel. Lastly, I see that Intel is prioritizing power usage and GPU over CPU performance in their next generation of chips, Haswell, and I think they will continue doing so in the coming years. It would make way for ARM to boost its CPU performance and for AMD to catch up with Intel's CPU performance, and I think it would be easier for ARM to improve its performance rather than it is for Intel to improve power usage and with the stunted growth of Intel's CPU performance would someday, be the cause of ARM processors levelling with their x86 counterparts. All that makes me think that it IS possible to make the world switch to ARM and that ARM would be the next "Intel".

So after that long useless explanation, let me repeat my question, in terms of performance, do you think ARM (especially A15) come close to non-atom x86 chips? If so, is it comparable to Core 2's (Conroe) or later versions?

You're also free to correct my statements.