A software program that is not developed any longer and assisted is said to be just dead, even if still working. The major problem not being an engine regularly running by itslef, but its interaction with other necessary layers of software like: operating system, word processors, characters coding ...
That's why that software application is said to be dead.  Somebody calls it "history". Is history synonimic with death?
From history we can learn, I dare say: especially if recent and part of our own experience.
We can learn, for example, that the present is not necessarily better than the past. Market supremacy does not always imply technological superiority. We might have the chance to observe that valid, outstanding, technology has been simply burnt out because of financial and commercial -more powerful- interests. We might have the chance to observe that noble products no longer developed, sometimes still working, and that ar part of history, exhibit features far superior to those of living, on-the-edge, continuously updated programs.
In our small context I can mention the Papyrus bibliography management software®  -still working in its own operating environment, freely downloadable form the Internet. Papyrus, for example, had unrivalled -to my limited knowledge- features in terms of thesaurus management and linking entries in lists and records in a database: features still lacking in living and leading products.
Another example is Procite, which development was abruptely interrupted when another company took it off from the owner/creator's own company in 1999. It lives now in a family with at least two other similar brothers, like EndNote and Reference Manager, and offers its source code unvealed to the firm which owns it. During these past 8 years Procite has literally given parts of his body to one or the other of the two brothers: subject bibliography, Z39.50 searching, citation style design, and recently the finical edit window configuration ... but Procite has still got features lacking in both or one of the other brothers. For example: rich and flexible search interface, complex query expressions, records group management.
Papyrus is not part of this review any longer because of lack of space (too many columns that have to fit in one page and yet be readable), but Procite deserves to stay where it is and helps our understanding.