Although the article does not focus on vertical integration, you might want to
take a look at Doug Gomery's "The Reagan Record" (Screen, 30.1-2, Winter/Spring
1989).  The postings already submitted on this topic give an idea of
how studios were battling regulation fifty years ago; Gomery's essay looks at
more recent deregulation.  Basically, thanks to Reagan, the studios don't have
to worry about getting busted for their distribution and exhibition practices.
I hate to sound like a dime-store Marxist, but the bottom line is that
deregulation means that the media(TV, movies, newspapers) are not answerable to
the government or to citizens, merely to "consumers."  Rather absurdly, this
means that if you think it is wrong that a producer controls the distribution
or exhibition of a product, you can "vote" against that product by not paying
for it.  If you are a corporation, you can "vote" against media concentration
by buying someone out.
H. Hendershot