Movies have always inspired fashion girls, and this suit is no exception. Even though "Bonnie and Clyde" would have been a few years earlier, the 1920's and 30's were a big influence in what was being worn during the early 1970's. One big fashion inspiration was "The Great Gatsby" with it's gorgeous dresses and suits.
From those movies came vintage looks that included menswear inspired suits.
Like this one: Look at the jacket details--it has fun little pockets, wide lapels and puffy shoulders, neat belt in back (hello, Marc Jacobs!), but the pants are what's really cool--they have a hi-waist with a really wide waistband and little buttons instead of a zipper. Then there are the gangster (as in 1930's style gangster) pant legs with wide cuffs. The girl in the pink is even wearing a beret like Bonnie wore in "Bonnie and Clyde". I am betting she made that suit from a fine wale pink corduroy. The short sleeves would have been truely a fashion statement in 1973 for the girl who wanted to be noticed with her vintagey (then) 1920's style pant suit.
The next time you consider trying on a high waist pair of pants, remember the 1970's as it portrayed the 1920's and 30's. We're just another link in the chain.