And in a world awash with tweets, Facebook postings and leaks, The Endless River, started by co-producer Phil Manzanera in August 2012, was kept under wraps until Gilmour's wife and lyric writer Polly Samson broke the news on Twitter in July.
Manzanera, longtime guitarist in Roxy Music and Gilmour's friend since high school, laughs about how long it took to get 53 minutes together.
When Gilmour invited him to listen to recordings of the band - Gilmour, Wright and drummer Nick Mason - improvising during The Division Bell sessions, Manzanera went through 20 hours of tapes and pieced together a musical arc: "To make it listenable it needs to be short so what's the shortest I could make it? Two double-sided old-fashioned albums.
"Classical music has movements so I could have four 13-minute bits. So I constructed a story and at the end of six weeks I went to David and gave him my narrative. He could hear some possibilities and said I should play it to Nick. And he said there were possibilities too.
"I thought, 'wow this is great'. Then nothing happened for nine months. Typically slow Pink Floyd."
The producer Youth - of Killing Joke, Paul McCartney's Fireman project and who recorded an ambient album Metallic Spheres with Gilmour - was invited to work on the tapes before Gilmour took control.
"In his studio in Hove near Brighton he inserted bits he liked and took out bits he didn't. So he got really involved, as he should. It became a Pink Floyd project."
Manzanera says pieces like Sum came from a jam where Wright played his old Compact Duo Farfisa organ - "and he hadn't used that since Dark Side of the Moon. And I wanted some of that French horn sound he did on keyboards for Wish You Were Here.
"Then I found a jam which reminded me of Echoes or Live at Pompeii and I thought, 'great, but it doesn't have a beat'. I found some drums where Nick was just warming up, made a loop and put it underneath the free-form bit. Basically I took diabolical liberties just to show David what could be done."
That Gilmour changed the shape of the music constantly - right up until eight weeks ago - doesn't trouble Manzanera: "He had to make it his thing, a Pink Floyd album and not a Manzanera version of a Pink Floyd album."
"Right from the beginning it was, 'what would a Pink Floyd fan like to hear?' This is for the fans, it's not trying to get new people in. It seemed to be saying goodbye as a tribute to Rick. But it was a slow cruise into the sunset rather than going out crash-bang-wallop.
"It was very much a hybrid and almost a documentary, capturing that last time the three of them jammed in a way they hadn't done since Wish You Were Here."
The final piece, Louder Than Word, has pointed lyrics by Samson: "We bitch and we fight but this thing that we do is louder than words... the sum of our parts." Manzanera sees it as "not only a comment on the album, but looking back on their working relationship".
And for longtime listeners - some will hear "classic Floyd" others "ersatz Floyd" - this farewell is an old-style experience. You send the wife and kids out ... ?
"Yes, and put the headphones on," he laughs. "We like to call it immersive. It's not for everyone, it's like classical music, you've got to sit and listen to long stretches of music.
"In this age everyone does short things for YouTube or Spotify. There's that playlist attitude where you take a track from here and another from there.a
"This is old fashioned in that it requires you to sit down, lie down even, and dream away."
- TimeOut
