Wayne M. Smith wrote:
  Often it simply isn't worth it to build upon
something unless you
 enjoy exclusive rights.  The restoration of old films is a good
 example.  The studios that hold copyrights to old pictures  
 spend huge
  amounts of money to restore the prints for issue
in DVD format
 precisely because they hold exclusive rights and can make back what
 they spend.  In the case of public domain films, this  
 simply doesn't
  happen. 
 Demonstrably false.  UCLA has restored many films that the
 studios weren't willing to spend a penny on; some still in
 copyright but most expired.  In general they've done a much
 better restoration job than the studios usually do.
  
Perhaps I need to write a bit more clearly.  The antecedent for "this
simply doesn't happen" in my post is "studios . . . spend huge amounts
of money to restore the prints for issue in DVD format."  UCLA, last
time I looked, is not a studio.  Academia is almost always an exception
to any general rule.