Alpha support was removed in one of the later NT5 betas right? Makes sense that it would've been late 90s then, before it was renamed Windows 2000 for release.
It was canceled essentially overnight by Compaq higher-ups, teams at Microsoft and Compaq learnt when they came to office. It was present on last release candidate before RTM, because it was essentially the only 64bit platform to actually fixup 32bit issues that prevented 64bit address space in earlier NT releases.
