"Stoney End" was Barbra Streisand's first move away from purely Adult material. I perceived it as Rock! She quickly retreated and didn't return until the Disco era.
Not quite.
The first move was her album "What About Today" from the summer of 1969. Three Beatles songs, a Paul Simon, a Buffy Sainte-Marie. Trouble was, her producers and arrangers (chosen by Columbia Records) didn't understand the material. The album stalled at #31---by far the worst of any non-Christmas album. Her previous low was #12. None of the three singles charted.
The "Stoney End" album was the same approach (songs by Joni Mitchell, Laura Nyro, Harry Nilsson, Gordon Lightfoot and Carole King), but with Streisand's choice of a single producer, Richard Perry.
The album went Top 10. The lead single, "Stoney End", peaked at number 6 on the Billboard Hot 100, but number 2 on the Easy Listening chart. Why? Because MOR/Adult Contemporary stations of the time weren't as limp as people seem to think.
The follow-up single was Laura Nyro's "Time and Love". Laura was on a hot streak as a songwriter---Blood, Sweat & Tears and the Fifth Dimension had big hits with her material. But hot on the heels of a top 10 "Stoney End", Streisand stalled at #51 with "Time and Love", though it made #3 on the Easy Listening chart.
The third single was also a Laura Nyro---"Flim Flam Man". Even worse. Peaked at 82 on the Hot 100 and #7 on the Easy Listening chart.
Streisand did not retreat---she doubled down. By the end of 1971, a new album "Barbara Joan Streisand", again produced by Richard Perry. Material from Carole King, Laura Nyro, John Lennon and a then-unknown songwriting duo---Donald Fagen and Walter Becker (only a year from launching Steely Dan).
The first single from that album---Carole King's "Where You Lead"---only made #40 on the Hot 100 (but #18 at KHJ) but a solid #3 on the Easy Listening chart.
The follow-up, John Lennon's "Mother"---was a disaster. #82 on the Hot 100 and #24 Easy Listening.
The album, though, sold respectably, peaking at #11.
After that, Streisand had back-to-back movie commitments ("What's Up, Doc", "Up the Sandbox", "The Way We Were" and "For Pete's Sake"), as well as a TV special ("Barbra Streisand and Other Musical Instruments").
At the end of that string, editing on the movie "The Way We Were" was finishing up and the film about to hit, so Columbia rushed an album to go along with it. Streisand only had time to record a studio version of "The Way We Were" different from the soundtrack, Stevie Wonder's "All In Love Is Fair", Paul Simon's "Something So Right" and Carole King's "Being at War With Each Other" (which Carole wrote for Streisand, but because of the film schedule, she released first on her "Fantasy" album).
The studio fleshed out the rest of the album with stuff in the vaults back to 1969. Looking at Streisand's choices, if she'd had time, it's pretty clear this would have been in line with what she'd been doing since "Stoney End".
This is getting (?) long, but after "The Way We Were" came "ButterFly", with songs from Bob Marley, David Bowie and Graham Nash, "Lazy Afternoon", produced by Rupert Holmes, with his songs, a Stevie Wonder track and a Four Tops cover, and then (following a classical album with Claus Ogerman), the string of hit albums and Top 10 singles from "Superman", "Songbird", "Wet" and "Guilty".
That streak began pre-disco, with "Evergreen", "My Heart Belongs To Me" and "You Don't Bring Me Flowers" (with Neil Diamond) before "The Main Event/Fight" and "Enough is Enough/No More Tears" (with Donna Summer) and "Woman In Love", "What Kind of Fool" and "Guilty" (with Barry Gibb).
So, Streisand never retreated---until 1985's "The Broadway Album". She just wasn't getting airplay.