If we're talking firmware, the gigantic mess that used to be called ACPI, still leave users suffering every day for example. And replace it with what? APM? I'

If we're talking firmware, the gigantic mess that used to be called ACPI, still leave users suffering every day for example. And replace it with what? APM? I'm completely unaware of another power management abstraction that has even a fraction of the capabilities and proven track record. Sure if your apple or IBM you can build a machine with a custom tightly bound firmware/OS/hardware interface that works well. But, if you look at for example the Arm ecosystems attempts to use DT in the linux kernel and manage everything from a heavyweight kernel it is a fools errand. It has successfully been failing for fully 1/2 the lifetime of ACPI. Never mind no one in their right mind designs a system these days where the big cores try to manage their own power/perf curves, nor even modeling the system power/cooling without using a small low power core continuously monitoring and adjusting the hundreds of fine grained power domains on even smaller machines needed to achieve modern perf/power parity. So please explain.