Detroit
 

If someone says Los Angeles has a bigger FM radio market than detroit because its more heavily populated, what does this mean in plain and simple English? More lucrative, more diverse, more cosmopolitan, ect…? What exactly would they mean by this?

On a very basic level, a bigger radio market can accomodate a lot more radio stations due to the fact there are a lot more listeners.

When i was living in la the fm radio stations felt more spontaneous vs houstons which were more low key, does this make sense? It doesnt mean they were bad or anything...

If you enjoy the stations in the Detriot area, that's all that counts. I do know that Detriot, being right across from Ontario, gets Canadian radio stations as well as US ones. Of course, in LA, some Mexican stations can be found on "terrestrial" radio. In fact, Stan Ridgway was inspired to write Mexican Radio for his then band, Wall Of Voodoo, from listening to a Mexican station while driving around LA.