In Singular Fashion

Grammar question: Why is the singular used when talking fashionista?

E.g.,
"The over-knee sock works with a short skirt."

"The wide-legged pant is effortlessly chic this season."

"That shoe is completely badass."

Ruthie Davis Shoes

"An opaque black stocking would look great with ... that ankle boot."

"A scarf would dress up that neckline."  (Okay, I get this one.)

"Bridge Bardot knew how to wear a great-looking boot."

1968, REX USA

When I am not freaking out about the ebola virus, I think in a singular fashion.