Much more than cool, there were practical reasons for urban drummers in big cities, where most of the jazz was located, to play 12/14/18 kits. As you mentioned, portability was a key factor for many drummers, including me. Try navigating subways and cabs in a busy urban setting with large drums, lot's of cymbals and heavy duty hardware. From the late '60s through the late '70s when I was gigging in Greenwich Village, Soho, and midtown Manhattan, ease of transportation was a significant feature of a kit. Smaller drum sizes with light weight stands, pedals and accessories, and compactness using a minimum number of cases was extremely important. I used my 20" Lugwig BD when someone was giving me a ride, but if I had to use a cab or subway it was always an 18" bop BD. To make getting to and from a gig more tolerable, I often played a simple two piece set in those days. I used an 18" inch bass drum in a case with a pocket in which I also stored an 18" thin crash/ride and a 16" crash. Along with that I has a specially sized and built small wheeled trap case that I had made for me at Frank Ippolito's drum shop. In it I kept my Ludwig Supraphonc with my 14" hats pressed against it in a protective bag, very compact and light weight stands and pedals, and all my sticks and brushes. In addition, I had the case sized so when I turned it on its side it served as my throne with a thin circular foam pillow I made myself and stored on top of the cymbals in the BD bag.As a result, I was able to navigate the streets, subways and cabs with just two cases, a relatively light rolling trap case, and an 18 inch bass drum case with a cymbal pocket. :)
Great point.
It cannot be easy being a gigging drummer in Manhattan! Buses, subways and cabs is not the easiest way to transport drums, and the cabs these days are sub compact jokes, not full size Checkers and Grand Marquis! Most of the clubs are pretty small and intimate anyway, so need for big kits.
There's a reason that the Gretsch Catalina's are such big sellers.