As much as I love the Holland's work on the last three records, I do wonder sometimes what would have happened if The Supremes got in on the ground floor with some up-and-coming producers at the time, like Nile & Bernard of Chic for example. Or if they teamed up with some Motown people they hadn't worked with yet, like Norman Whitfield or Willie Hutch.
There's also the self-titled album by the Detroit sister trio
Three Ounces of Love that came out on Motown the year after The Supremes disbanded. I sometimes listen to that wondering whether that would have been a Supremes album had they continued. It featured many of the same producers and arrangers, like Greg Wright and the Holland Brothers, who were also on the last three Supremes records.