It seems you don't understand that you can port any code from x86 to ARM. The reason why you have mobile-kind apps on a phone or tablet is because it is a mobile device, not because it is build over ARM.
Yes with enough work it can be done, but it's not easy and takes many man hours to port something. It isn't free.
Oh and you can't just port some code without some abstract functions. For example neon does not have a movemask instruction. It takes about 10 custom dependent instructions to implement.
Every platform has its own ecosystem but there are tools to facilitate overlap. LLVM Compiler is a great example.
Nothing is going to happen overnight. It will be years to decades from entry point to market capture.
Desktop workstations, developer kits, servers, and supercomputers based in ARM aren't executing mobile apps.
E.g. scientists using Isambard are running high-performance code to solve compressible Navier-Stokes equations for shock-boundary layer interactions. And they are doing that on ARM hardware because the code run faster than on any Broadwell or Skylake Xeon.
source on the custom code faster on ARM?