It was dropped because Microsoft felt it was inappropriate or embarrassing to ship an app that they themselves could not port to 64-bit, at a time when they were asking 3rd party developers to do the same.
Raymond address that in his reply to the first comment on TFA.
"That would have been even more work, because there was at the time no infrastructure in Setup for having 32-bit-only components. (And then automatically uninstalling it when WOW64 was disabled.) ..."