My bet: backwards compatibility. Better power management requires changes in behaviour of the OS and it is very hard to change behaviour without breaking things.
Suppose the USB sleep state handling code is suboptimal. Is that because programmers paid less attention to power usage a decade ago, or because some devices implement a power state incorrectly? If the latter, which devices? If Microsoft isn't 100% sure they know of all devices for which it is needed, they may choose to leave the less efficient code in place regardless of whether a deficient device is plugged in.
An example might be a pet peeve I have with Windows: its tendency to 'discover new hardware' when one plugs a bog standard mouse or keyboard into a USB port for the umpteenth time. That in itself is baffling, but it can take Windows half a minute or so to figure out that it has a driver for the device and start it. I do not have the faintest idea what it does in that time, but it must be unavoidable within the constraints microsoft sets itself, since it hasn't been fixed in a decade or so (but it has been improved quite a bit) and I bet it must have itched quite a few engineers.
Whatever the cause, plugging in a USB mouse must use way more power on Windiws than on a Mac.
An example might be a pet peeve I have with Windows: its tendency to 'discover new hardware' when one plugs a bog standard mouse or keyboard into a USB port for the umpteenth time. That in itself is baffling
It's not baffling, it's manufacturers implementing USB standards improperly, and Windows doing the least-bad thing.
Suppose the USB sleep state handling code is suboptimal. Is that because programmers paid less attention to power usage a decade ago, or because some devices implement a power state incorrectly? If the latter, which devices? If Microsoft isn't 100% sure they know of all devices for which it is needed, they may choose to leave the less efficient code in place regardless of whether a deficient device is plugged in.
An example might be a pet peeve I have with Windows: its tendency to 'discover new hardware' when one plugs a bog standard mouse or keyboard into a USB port for the umpteenth time. That in itself is baffling, but it can take Windows half a minute or so to figure out that it has a driver for the device and start it. I do not have the faintest idea what it does in that time, but it must be unavoidable within the constraints microsoft sets itself, since it hasn't been fixed in a decade or so (but it has been improved quite a bit) and I bet it must have itched quite a few engineers.
Whatever the cause, plugging in a USB mouse must use way more power on Windiws than on a Mac.