There's an x86 processor in your desktop, but there are many more RISC processors doing things like controlling your hard drive. If you buy an AMD processors there's even an ARM core inside the x86 processor in the Platform Security Processor.
Add in all the microwaves, routers, the many processors in your car, and so on and 99% seems a bit high to me but not unreasonable.
Seems disingenuous though, as the two markets have totally different optimization points and volumes. More like RISC has won the low-cost, low-power market, and CISC-RISC hybrids won the performance market, or something like that.
I'm sure you can think of a million other markets like this- sedans vs race cars, fighter jets vs puddle jumpers, etc.
It's really a lot more than two markets. The high end communications systems that use MIPS have almost as high performance demands as a desktop or server. And currently the highest performance core is a POWER 9. But on the other hand you have a few places where x86 Atoms have made inroads as embedded cores, as in the UR robot arms I work with.
But really I think we really do overemphasize the importance of x86 because that's the architectures we have the most experience working with directly.
there's a really interesting market at the bottom as well - super low power CPUs. 8/16 bit stuff, not RISC at all (since DRAM itself is a huge power draw at that level), and so on. fun stuff.
Smart TVs, Digital Cameras, Thermostats, Wristwatches, Phones, Tablets, Printers, Google Home devices, Amazon Echo devices, TV sticks (Chromecast, Firestick etc), Ring doorbells, security devices, etc, . . .
Anything (like a Printer) with a web based interface, having a micro web server within the device.
There are VASTLY more ARM and other architecture chips than there are x86/64 chips around you right now. Possibly even in the computer monitor you're reading this on. The desk phone in your office.
Just about anything that has any kind of a screen with menu system.
Add in all the microwaves, routers, the many processors in your car, and so on and 99% seems a bit high to me but not unreasonable.