Joshua posted to the Suggestion Box, "Around the time of WinXP SP2 x86, the API hook mechanism was standardized. Why wasn't the same thing done for x64?"
Who said it was standardized for x86?
Hooking APIs is not supported by Windows. There may be specific interfaces that expose hooks (like
CoRegisterInitializeSpy to let you monitor calls to
SetWindowsHookEx to let you hook various window manager operations) but there is no supported general API hooking mechanism provided by the operating system.
So I don't know where you got that idea from.