The thing that made x86 take over the world was the immense scale and volume it got from the PC clone and small PC-based server (NT and early Linux) market. It

The thing that made x86 take over the world was the immense scale and volume it got from the PC clone and small PC-based server (NT and early Linux) market. It allowed huge R&D investments and let x86 eat more expensive workstation and server CPUs from the bottom up, eventually conquering the server and then cloud. ARM got the same thing from the mobile phone market, allowing it to eat x86 from the bottom up in exactly the same way. It went from phones and IoT, to laptops and small servers, and now to large cloud servers. ARM does have a small advantage from its ISA being much easier to decode, especially with a wide decoder, but x86 engineers have shown that they can stay competitive.