It wasn't as widespread and the powers that be didn't have the means to deal with it. How were they to stop people from making copies in their own homes with no media protection and not wired to anything like the internet? There have always been copyright disclaimers on media products. At that time, technology wise, saying "don't do it" was the best they could do.
Audio quality of copies could also be said to suffer somewhat from the original, which was itself suspect for some sources. Copying a file doesn't result in the same diminished audio quality. -- "...but ya doesn't hasta call me Johnson!"