Saved by the Concept album

Well, Glass Hammer's Chronometree is a concept album about listening to concept albums...

Many concept albums don't have that much of a concept anyway. Concept albums often times could just be released as a non-concept album. Pain of Salvation's Remedy Lane include songs that were written without a concept in mind, and those songs were included merely because Daniel Gidenlow "think the song fits on the album" (paraphrasing). If you look at the other albums by Pain of Salvation, they also deal with the same topics, so I'd bet if "Her Voices" (a song from The Perfect Element album) were written in 2001, it would also be included in Remedy Lane. Concepts can be loose, it's the core ideas that need to be tight, and that's true whether or not it's a concept album.

There are albums like that in hip hop and possibly other genres. But prog rock is not a stupid genre so there won't be a prog rock album about making concept albums. Not saying hip hop is stupid, but hip hop artists do talk about themselves and their albums an awful lot.

For example Eminem's Recovery spends a good portion talking about how this album is the recovery album and something like that. Self-referential concept. This has been going on for decades - 80s hip hop classic Paid in Full could be seen as a concept album about how they made that same album and how they were famous because they released that album (makes you wonder, if the events take place after the album's release, how could they talk about them in the album?).