It was the economies of scale and the standardization on x86_64 that made the PC the performance king in the first 2000s decade. Intel (and, of course, AMD) x86 did not have the best ISA but they, because of economies of scale, had the best fabs which let them outperform anything else.
While Intel was dominating with raw performance in the first 2000s decade, embedded chipsets slowly coalesced around the ARM ISA, a process which was accelerated by Apple choosing ARM for the iPhone (Nokia also used ARM in a lot of their phones).
Moore’s Law finally stopped working for Intel and they stopped being able to outfab everyone else in the mid-to-late 2010s; a 2012 x86 chip has about the same performance as, say, a 2017 x86 chip.
Intel saw the writing on the wall with people using non-Intel ISAs for phones, and tried to make an Atom chip which would work in a phone; it was a flop. Nobody wanted the x86 ISA unless they needed it in systems which ran legacy applications.
With the Raspberry Pi moving up from only suitable for specialized embedded applications to having near-desktop level performance, and with Apple finally making an ARM chip which is competitive (and in some cases superior) to Intel’s desktop chips, and with legacy x86 Windows applications being in many cases replaced with webpage and smart phone applications, it looks the industry as a whole is finally moving past x86 and its bloated instruction set.
This is a much needed breath of fresh air for the computer industry. I like the M1 because I like that we now have mainstream non-x86 desktop/laptop computers again.
I think RISC-V has a lot of potential, and I am interested in what comes of it in the 2020s, whether it blooms like the ARM did, or if it goes the way of the HPPA, Alpha, or Sparc.