It could mean it is outdated or long gone. It often means something cannot be found or recovered and has been lost forever.

Means "потерянный во времени" in Russian.I think it is possible to say about the person who is a kind of old-fashioned or has not "modern mind".In Russian it has such meaning.

I 🤔 think it friends on the context this phrase is used in.

Thank you everyone. Can I use this phrase in the following context Person1: Have you watched the movie "What's eating Gilbert Grape"? Person2: I love that film. One of my favorite movie growing up. But now it seems lost in time. Is my understanding correct?