That just means despite losing "potential income" the industry is still managing to earn money via people who do not wish to circumvent Copyright Law. Or in other words, the number of people not interested in infringing copyright is greater than the number of pirates. That doesn't mean anything other than a majority of people respect copyright law.
>So piracy (at least, as we have known it) is not harmful, in fact it seems almost certainly beneficial economically
Please link to data that demonstrates piracy is economically beneficial to everyone. Since you're claiming 'almost certainly' - I assume you can find hundreds of studies.
Here is my simple thought experiment. Let us say it was impossible to pirate Windows or popular games or tv shows and people had to pay the $100 or w/e it is. Would every single pirate switch to Linux, free games, non-copyrighted entertainment OR Will some of them end up paying the $100?
If reducing Windows piracy means more Linux adoption, I wonder if the Linux cheerleaders would be onboard to reduce Windows piracy :)