I just read of this on the Supremes' Wikipedia page.

In 1982, around the time that Motown reunited all of the Temptations, it was rumored that Motown would reunite the Supremes. The 1974 line-up of the Supremes [[Wilson, Birdsong and Payne) was considered for this reunion, which was to include new recordings and a tour. Under advisement from Berry Gordy, Wilson declined to reunite, and the idea was scrapped

Forgive my ignorance, but does this mean that Berry Gordy advised Mary not to reunite, or did Mary not take his advice to reunite? I think it is the latter.
If it is the latter, that Mary declined to reunite after Berry advised that it would be a good idea and would back her with new recordings and a tour;
then Mary made a mistake in my opinion. At this time, she was touring with every configuration of the Supremes' name in her billing with two non Supremes.

https://en.wikipedia.org/wiki/The_Supremes