I don't think this problem is worth the pain of DRM, but it is a problem nonetheless.
> it is a problem nonetheless.
It's just that:
1. The Internet has made distribution trivial.
2. The price-point is now 'free' instead of 'cheaper than the original, but still costs money.'
3. Storage is now trivial. It's easy to pirate a 1000 PDFs of actual books. It's less trivial to deal with 1000 actual books, even if they are free.
In general though, when people are arguing that the pirates wouldn't have paid for the product at any price, they are attempting to dispel the myth that 1 pirate download = 1 lost sale. It's this calculation that is used time and again to 'prove' how much of an issue piracy actually is.