I really hope that wizards isn't holding off because of piracy, if so I need to go find them and tell them to get out from under that rock they have been living in. That myth has been debunked a long time ago if they choose a reasonable price for them. My references? Steam, Good Old Games, iTunes, Pathfinder, Netflix etc etc. Yes PDFs will always be pirated, right now it's the only way you can acquire them, and those who want to will. Might as well at least give us an OPTION to pay. Right now it's an annoyance at best waiting a week for someone to scan the books. Not that I pirate or anything....
Unfortunately, this is about revenue streamlining. In simple terms it is to make as much money as possible within their "quarterly" quota's before said product goes into decline.
Personally all they have to is for them to Apple and distribute there products through the i (everything) media site that they have,
I know of a game company that only uses Apple for that explicit purpose.
So again this is all about squeezing every amount of revenue out of said product.
Not about piracy.
I'm not saying you are wrong and I admit I have very little knowledge of corporate business but perhaps you could explain a bit more indepth about this revenue streamlining? I can't possibly see any way that releasing a PDF would do anything but help their money intake.
Is there a game store lobby? Maybe the game stores or the distributors like Diamond put pressure on other WoTC product purchases if digital copies of D&D core books are made available?