Suzanne Pleshette wore the long down to her knees tops quite often like Maude (Bea Arthur).
Apparently they were quite popular in the 70s. I was around in the seventies and I don't remember seeing them. I read Bea Arthur wore them to compensate for her height or whatever.
Suzanne Pleshette had nothing to hide or to compensate for. Probably just her choice of style.
Maybe she had a thing she was sensitive about her caboose.
She went on to wear the style long after tbns in later years. I just found it kind of an odd style for such an attractive woman.

I was in High School from 1970-1974.
When the long skirts & shirts came into fashion some girls liked them and almost ALL guys did not. LOL
Suzanne Pleshette's butt was a bit larger than she probably preferred but it was fine overall. Seems she usually dressed not very sexy over all but there were some scenes where she has cleavage and tight skirts & pants +-
She was a beauty in my eyes !