Ahh, looking down below at the first response there's a link to a '95 comp.lang.logo post with a great looong item by Leigh Klotz on the history of that. His claim was that it was legal wrangling between NSF and MIT on the licensing that caused the delay. This seems highly believable.
This person then did work for Logo Computer Systems on the competing version of Apple II Logo.
I'll message him and ask him to respond.