During Charles Dickens' early career, his books had no copyright protection in America, and British copyright law could be evaded by just changing the protagonist's name to "Oliver Twiss". He was still able to become independently wealthy.
By the time the copiers did that, and were able to get their copies to America, the authorized copy was already here, and most people who wanted to buy had already bought an authorized copy.
Even for works not in serial form, the authorized release had a big advantage, at least if the author was well known. Most sales occurred fairly soon after publication, and by the time copiers could buy a copy, and get it typeset (remember--this was all done by hand back then!) there weren't a lot of buyers left.
Stephen Breyer, who later went on to become a Justice of the Supreme Court, wrote a famous law review article called "The Uneasy Case for Copyright" where he argued that copyright might be unnecessary because of the market advantage from being first that the author's authorized edition gets. There's more information on this article here: http://en.wikipedia.org/wiki/The_Uneasy_Case_for_Copyright
Subsequent technological advances have pretty much obliterated the basis of that argument. Copying is so fast and easy now that being first gives very little advantage.