"intasa" just means "has been forgotten" in some dialects of Arabic. I think you are reading too much into the "once been famous" bit. "insa" is a word from the same root that means "forget it". I actually think both words are still in usage. Probably the more accurate translation is, "it was once known (i.e. known to all within the community) but has now been forgotten". Famous is less accurate.

It is used for mundane things. For example, the location of an abandoned water well.