As you point out, Intel's x86 devices are still 80% of the non-apple market. But the new M-series instruction set will allow better scaling of out of order instruction execution. My question:

Is that a big enough difference that finally the x86 line has hit a dead end, and Intel must switch?

Second question: If Intel does need to switch, can they do it, or will the M-series by so far ahead, that PC makers would start using the M-series based systems?

I guess the second question kinda comes down to Microsoft. If they produce an OS that runs native on a new instruction set or not.... and then of course the PC-dev community. Any reading of the tea leaves here?