IMO, abandonware means software that is a dead-end upon its very release, with no hopes or plans for anyone to every build upon it. Abandonware is generally not extensible, follows no good design philosophy that would let someone else build it up, and embodies essentially nothing.

Even a 100-line throwaway Python script has more utility to someone when it is published on PasteBin or whatever. But something like a binary executable released with no source code, with no support, and with no intent by the developer to ever make anything more of it, that’s abandonware.