Boston for original music, which has changed somewhat because the Rent Is Too High, but there used to be a perfect balance of young folks who stayed after graduation from whatever local college they went too, Venues at different levels (dive bars to halls to show biz), music schools, rehearsal spaces, recording studios and college radio that played your music, recorded or live. (both MIT and Tufts had live local in house performance shows). Touring was also afordable. These days for professionals and students that can afford the rent, there are Porch Fests (like open studios for visual artists) and for street band players, HONK in Davis Square Somerville, and that's a world wide draw. (my favorite street band is Rude Mechanicals from NYC, but Boston has Second Line and Emperor Norton's Stationary Marching Band)
I used to see Athens GA in a similar category, and NYC (although different lifestyle), in the 90s, Seatle of course.
You might consider that all to be developmental scene because a living isn't being made until you have a commercial hit. (Like the Mighty Bosstones, Dresden Dolls, Morphene, Pixies, or Amie Mann) There were no coverband venues at all, nada. I haven't seen a cover band since highschool in the 70s... But jobs in the field your degree is in are plentiful. Jobs in classical music and music education are also possible if you are in the top 2%.