No research is "permanent" - fields grow and change. Unless it is genuinely new or ground-breaking, or de nuovo in its field - then it is replaced and superseded eventually by new findings in so many fields. It isn't about ego (as I see it) - it is about contributing. I'm unsure if the work I published early in my career is still available - because I haven't looked .
Research is like a roller coaster it's fun while it last. I enjoy putting research in action in the field. Push onwards towards new and beneficiaries of science.
Everything has a shelf-life. Even the King of England's second son felt that his shelf life was limited. We are beginning to learn that cloud storage is limited. My art school has the same problem we no longer have access to all the lessons that we had from 4 or 5 years ago. Sad but it is the way the world works. We are so fortunate to have this awesome resource.