Most signs point to it being hardware-related. Without any Mac-specific optimization, the Asahi folks got fairly long runtimes out of the CPU (which makes sense, ARM has low idle draws).
Frankly though, I don't want most manufacturers to make ARM machines. While Apple is allowed to monopolize the latest TSMC silicon, it's completely pointless trying to compete with them. May as well focus on delivering a great x86 experience with AMD and switching to something more open like RISC-V when the time comes.
I agree with your sentiment for the most part. I would love to see someone take RISC-V or Power seriously to compete in the consumer space with an ISA. However, I don't think Power is quiet cheap enough and Risc-V just isn't there yet. So I'd like to see someone throw their hat seriously in the ARM ring until Power becomes cheap enough or RISC-V gets there. Plenty of people producing Intel/AMD machines, we have too many there.
Frankly though, I don't want most manufacturers to make ARM machines. While Apple is allowed to monopolize the latest TSMC silicon, it's completely pointless trying to compete with them. May as well focus on delivering a great x86 experience with AMD and switching to something more open like RISC-V when the time comes.