It's expensive to location shoot.
Time was a series would travel out of LA and do extensive location shooting. On the other hand, at the same time, there were shows which stayed in the LA area and relied on cover shooting (Establishing footage that is either archival or is commissioned for the show), to create the illusion of another place. Think I Spy for the former and The Man From UNCLE for the latter.
I Spy shot for several weeks in Hong Kong and several other locations before returning to Hollywood for interiors. UNCLE worked on the MGM lot and certain close areas round LA. There are lots of examples, but since I like spy shows.....
Interestingly enough, there are shows which film elsewhere aka not all in Hollywood.
Gossip Girl, a youth oriented night time soap, is filmed entirely in NYC. The Vampire Diaries, a youth oriented vampire soap, was originally filmed in Georgia as was October Road. There are other examples but you should get the idea.
Alias, the spy show with Jennifer Garner, was filmed in the Los Angeles area, with establishing cinematography for the globe hopping action. And that's the case for Close To Home, a cop drama ostensibly taking place in Indianapolis, but filimed similarly to Alias.
Stories can be told wherever you are. It depends on all the factors, including writing, acting, camera work etc.
Most of all it takes imagination. And it takes purpose.
What stories do we want to tell?
The sky is the limit.