In mobile devices, ARM has an almost(?)-monopoly indeed, but x86 never was a serious contender in that space to begin with. The same goes for "IoT" devices. In new areas of computing, Intel is just one vendor among many (well, several), and the more the market tends to demand low-power chips, Intel's advantage melts away. In that sense, I agree with you. In HPC, I could see ARM become a serious alternative, because the trend seems to be to delegate the heavy lifting to GPUs, anyway, and the GPU does not care what kind of CPU feeds it, so to speak.

But in the traditional desktop area, if you cannot run Windows and the huge number of third-party applications available there, you might as well give up. And to completely "replace" x86/x64, you have to compete in the desktop market as well.