NTFS hard links have been available since NT4, released 31 July 1996.
¹excepting the recent change where a "developer mode" can be activated, but that still doesn't make them useful on an end user's machine, or to an end user.
Of course that's a bit of a lie, if you use the NtSetInformationFile api you don't need write access :-)
To be fair it was first with Vista that Microsoft tried to seriously lock users down and keep administrative privileges far away for the common user.
I'm pretty sure most Windows 2000-users had admin rights. This was not the reason symlinks was not adopted.