This isn't just a question of direct power management features or use of custom silicon, but there has been curious noise for years out of Apple over a major ca

This isn't just a question of direct power management features or use of custom silicon, but there has been curious noise for years out of Apple over a major cause: memory management. In modern systems memory becomes a major source of power consumption, so reducing how much if it you need to keep active results in big gains, on top of all the other benefits of doing this. This is partly used as the reasoning to explain why Swift has evolved in the direction it has, but also various apps that suspend/resume their state at a higher level than simply relying on the OS to do it. It would take a gargantuan effort, which would likely annoy almost everyone, to get a desktop Linux distro to do this.