Welcome to ARM
It is the joy of allowing vendors to tinker with the system
On PC, the tinkering ended within 1-2 years from the start. From there it was all standard and all an IBM clone. That has allowed a single system to exist.
Arm, MIPS, PPC, etc are not there yet or have been artificially prevented from getting there. So it is natural to have a Win-why-should-I-care-now...