Well said, Parama.
Regarding it being one song, I think certain musicians get hung up on having super long songs, like it makes them more prog or something. Same thing with Transatlantic's The Whirlwind, which is quite clearly a suite/thematic album, but it comes off as more prog to call it a 77-minute song, so they did.
The point: when taken as a single song, yes, Six Degrees is very messy, but as a suite where all of the movements can be taken individually, it's really not.