Southwest does not have a "hub" anywhere. They call them "focus" cities. Just the name is different. Chicago Midway is one of Southwests major "focus" cities. Baltimore is another. Many flights in the east stop at Baltimore on their way to an ultimate destination.
I have traveled KBWI to and from Hollywood / Ft Lauderdale in the past year. WN272 which I used returning KFLL to KBWI a couple of weeks ago routes:
KFLL-KBWI
KBWI-KSTL
KSTL-KTPA
Ft Lauderdale to Tampa via Baltimore and St Louis. The "focus" at KBWI is great for me since I live near BWI and I can get non-stops to 30 or 40 cities on WN.
Cows has declared Open House.
seacue