Do you remember the 1990s everlasting arguments about RISC vs CISC? There were so many arguments (online and magazines) saying that "soon" RISC would eat CISC. And yet, it never happened. I'll be dead before the demise of x86. More likely: The computing landscape will get more complex. Probably ARM will become a legitimate competitor to x86 outside of handheld computing, and RISC V will become a legitimate competitor to ARM for single board and handheld computing.