Re: Linux has facilitated the cituation he is lamenting about
The Windows-Ubuntu subsytem is much "easier " to implement - it translates Ubuntu kernel calls into Windows ones, but everything is still x86 (and, AFAIK, command line only).
Emulating a CPU is an heavy task (look at IA-64 when it had to run x86 code...), and Windows RT is not a full ARM implementation of the "NT" kernel and "Win32" subsystem, thereby nor simple recompilation works nor emulation is an easy task.
Windows NT was truly multiplatform because it had everything - HAL, kernel and user space subsystems - each running natively on each supported CPU. The HAL never abstracted the CPU code - it just abstracted the hardware architecture interaction (i.e. hardware I/O, physical memory managment, etcl). Note that HAL also allowed systems which used x86 processor but didn't follow the IBM PC architecture to run Windows.
It could done, of course - but depends on the ROI. Back then it was clear that Alpha and MIPS CPUs would have no brought enough money.