> I also don't quite get why Intel doesn't just design their own competing high efficiency architecture, after abandoning x86 and backwards compatibility, of course, something they should have done two decades ago at least.
They've tried, at least twice. Itanium and Atom come to mind. It turns out, it's not as easy as it sounds, even back when Intel was near the top of its game.
Atom cores are x86, and aren't just close; they're near exactly the same. They use the Gracemont microarchitecture in the Efficiency cores, which is the fourth generation Atom built on Intel 7.
My understanding was that Atom was x86 instruction set (or whatever Intel calls amd64?), but its own arch. I very easily could be wrong about that though.
Itanium was supposed to be powerful, not efficient, and it originated at HP. Atom was x86. If Intel designed something new from the ground up with high efficiency specifications, I don't think it could be too terrible, and I think it would advance SotA to have real competition with ARM designs. The i860 may be Intel's last innovative chip design solely designed in house. Every advance in x86 is just another ugly monstrosity.
Intel bought the StrongARM line if ARM cpus from DEC (used in some PDAs of the late 90s) and rebranded it XScale. Had some minor successes, but no huge design wins. Sold it to Marvell in 2006 right before the iPhone was released and smartphones exploded the market for ARM cpus.
They've tried, at least twice. Itanium and Atom come to mind. It turns out, it's not as easy as it sounds, even back when Intel was near the top of its game.