I think the subject is not so philosophical. The "musical resource" of making a song and then a "Reprise" was already common. In some cases such as Sargent Peppers the band thought it nice to open with the "1st" song and close with the Reprise (ok, we still have A day in the life but the Reprise feels nearly as a closing).
Prog bands started to employ also the resource of defining tracks as splitted into Parts or Movements. It was only a matter of time that someone would combine both ideas and open an album with a certain theme and close it with other Movement(s) of it. I guess it felt kind of cool, even if sometimes the 2 parts have not much to do with each other musically.
Another example is the excellent debut album of the spanish band Iceberg, "Tutankhamon", which starts with the instrumental "Tebas" and closes with "Tebas Reprise" (in this case they are really slightly different versions of the same musical theme).