While watching the LAFCPUG “X Night” videos I noted that Michael Wohl advises that “all edits should be in V1” and not doing that is a sign of a failure to commit.  Similarly reviewing some FCP 1 release videos, they once again (and again from Michael) seem to advocate a mostly single track approach.  That would certainly parallel historic ways of working with video or film where only one track, or an A/B configuration was standard.
I think the use of tracks has evolved since then. One of the reasons that people became concerned when Final Cut Pro X took away the traditional track layout was simply because those tracks have become valuable metadata. A typical audio example might be