Someone correct me if i'm wrong. But I was thinking about something for a while...
I notice that every city that gains musical corporate interest, has a signature vice or two that can be attributed/branded to that city.
In east coast cities it's (mainly) hustlin
In the West it's (mainly) gangbangin
In the South or Midwest it's (mainly) pimpin
I'm not saying these vices are specific to each region; every region got everything goin on there. But as far as mainstream branding goes.
Once a city has something on lock, then cacs swoop in and take a bunch of artists who made it out via that vice, and give them successful careers. Those successes serve as a beacon that attract would-be-regular nikkas to that vice/lifestyle, and rapping style. The artists who never were about that life are stuck making generic songs about "making it", and love songs. Their success tends to be limited.
as far as the question goes, I'm not sure what signature fukkery DC/ B'more bring to the table that would make cacs wanna start signing a buncha DC/B'more nikkas. You know how these folk are.
But DC got a wide variety, the oddisees, shy glizzy, fat trels, Wale's etc. B'More/MD got the mully mans, Phil Ade, etc.
I'm not sure if this post fits the question, but something told me to finally say this shyt in here