Autodesk never killed it AFAIK, it died on it's own. By not releasing service packs or future versions, it managed to kind of kill itself.
As far as the compatible data... AFS and LDT were virtually 100% incompatible, as far as native file formats go. Best I can remember, only the DWG file could be read by both applications. That was another gripe from the LDT world. Everyone thought AFS was going to be "LDT Lite" and it wasn't even close. Carlson's file formats, lack of a project manager, etc. meant that the only way to share data was via LandXML, and you can do that with Carlson Survey, Eagle Point, etc.
I'm glad there is someone out there who thought this was a good package, because believe me, I heard the other end of the story daily...