Let's say you've got something that needs to be computerised at a slightly higher level than an Arduino, with the computing part costing less than about $100-150, and ideally less than $50 (think Beaglebone, Odroid, PCEngine, Pi and clones, Pine, etc). It looks like the only choice is between Arm at the low end and x86 at the high end. Everything else has fallen by the wayside: The last MIPS-based product was the Ci20/Ci40 from 2015 and neither the hardware nor software have been updated since, PowerPC is out there but only as high-priced SBCs and good luck finding a distro that supports it, Sparc is left with Fujitsu working on it for mainframes, and RISC-V is still a glint in everyone's eye - the few SBCs based on it cost more than a low-end server, and despite various enthusiastic press releases I can't see any timeline where I can get a $50 RISC-V device that performs the same as a $50 Arm-based one. And then there's the software support, once you leave the x86 world you've got, outside of various specialised RTOSes, Linux. A very few systems have one or two of the BSDs, often in a hit-and-miss manner, but that's it.
Has Linux + Arm/x86 killed everything else?