With the initial boom of companies like Marvel Comics and DC
Comics, everybody was based out of New York. it was pretty much
understood that if you wanted to be involved in comics, you went to
New York.
With the booming of the internet, there is a lot more freedom
for comic creators. While Marvel and DC Comics both have their main
offices in New York City, creators are spread all over the
country.
There is a large concentration of creators in California right
now, and there is a chance with the recent changes in DC Comics
editor line up, it is possible DC might be shifting their base over
to California.
At this point in time, somebody wanting to break into comics,
could pretty much do it anywhere.