Pirating porn is a somewhat sophisticated computer activity. If you are savvy enough to have found this site, and are able to successfully download and unRAR a series of links you are more net savvy than most computer users.
There is always going to be a majority of netyzens who simply are unable to understand the techniques of pirating and will buy.
I'm going to say that the majority of porn afficionados don't have the skill to do this. Those folks will buy not pirate. I do a lot of computer support and if my client can right klik a mouse I consider that a milestone.
The software industry has plenty of customers who are incapable of pirating. Maybe the majority. I deal with them all the time. Just look at some of the questions posed here on this board, such as 'How do I download from Filesonic?' or 'Can you repost on Rapidshare, I can never get Sharing Matrix to work?'
I frequently try to instruct people in the art of downloading and unzipping. If I don't hold them by the hand they would never get it. Nope, the software industry (and the porn industry) will easily survive any possible losses from piracy. There are simply too many folks out there who do not have the skills to pirate.