Mac OS X has direct linage from NeXTStep that was first released in 1989 -- four years before Windows NT.
When it was originally rebranded OS X there was so much backlash from developers and Apple had to go back and spend a year creating a new API (Carbon) to mimic the one in Mac OS classic.
There is no reason to complain about "backwards compatibility cruft". An OS exists to run software and an OS that runs less software is less useful. Over time this backwards compatibility stuff is less and less significant -- you can run several copies of Windows 95 entirely in the L2 cache of a modern system.
When it was originally rebranded OS X there was so much backlash from developers and Apple had to go back and spend a year creating a new API (Carbon) to mimic the one in Mac OS classic.
There is no reason to complain about "backwards compatibility cruft". An OS exists to run software and an OS that runs less software is less useful. Over time this backwards compatibility stuff is less and less significant -- you can run several copies of Windows 95 entirely in the L2 cache of a modern system.