Re: Installed base
Intel moved to a RISC core ages ago. It makes sense. The x86 architecture, based (sort of) the VAX architecture is successful because of the RISC simplicity. They also have had a lot of expertise in build RISC processors: the 80960 was a processor I worked on.
And as someone pointed out: more ARM processors get shipped than x86 chips.
If you ever have to use AWS, you will see ARM processors as options. I have seen this story before: IBM had to lose market share on the lower end (they were EVERYWHERE) to DEC PDP/VAX which gave way to Sun Sparcs, which gave way to Intel, which gave way to ARM.All of this was happening at the lower end. And soon, the scale of the invasion overwhelms the entrenched processors.