Why didn't Motown like Mary Wilson?

[Ollie9]

Not a criticism by any means, but i think Diana has always been totally immersed in her own family to have spent much time grieving over Mary Wilson. The two women had not been friends for many years, who were at the end of the day work colleagues from over fifty years ago.
With Flo i would imagine it was the shock of her passing at such a young age, with the funeral being almost a precursor to Motown 25.