Obscenely large fines (see the RIAA) don't work (to stop all pirates, they do deter an unquantifiable number). People still pirate stuff. Ignoring it doesn't 'work' in that you'll have X amount of lost sales. This being an unquantifiable number. Plus as a creator/coworker of creators/employee of said rights-holding company there's a level of irritation caused when you see something you worked on being distributed for free.
Internet taxation to distribute the money to 'those who get pirated' isn't going to work (see CD-Rs in Canada). Likewise excessive computer monitoring will just turn into a tech race between the pirate and the companies being paid by rights-holders to do so.
There's no easy solution on this one. And all those people saying 'companies should find a way round it' might as well say 'someone should invent cold fusion'.
Fundamentally, the business model has to change. Companies have to recognise that their products
will be made available online, and
will be appropriated by people for what those people think is a reasonable price. They also have to recognise that
some piracy is inevitable, so they'd be better placed making some money from the online offering, but accepting some online wastage. Oh, and finally, they're going to have to recognise that their products lose their value
very quickly - if they can't recoup their investments within a couple of months, they're probably never going to do so.
What this means:
1) Everything that it is feasible to make available online must be made available online. If WotC don't make the PHB2 available for sale as a PDF, it doesn't mean it won't be available, just that they won't be getting paid.
2) Prices must be reasonable. Sure, WotC have every right to sell a PDF of PHB2 for $40, but the voice of the market appears to be fairly loud on this one: people won't pay. But they might pay $20, or $10, or $5, and depending on the price and customer numbers, that might end up more profitable for WotC. (Ideally, they should also provide a discount for people who own the physical book, or even just waive the charge entirely.)
3) To be honest, I think a subscription-based online library may be the way to go. Rather than ask people to pay even $5 for the book of the month, WotC might be better placed offering access to
all the D&D books (right back to OD&D) for a subscription of $10 a month, probably as an adjunct to a DDI subscription. (New books should be added to this as soon as they hit the stores, of course.)
4) To keep people paying, there needs to be a value-add that is not just the books. As I said above, I think they should tie it to the DDI, some of which requires an ongoing sub to be useful. Perhaps they need to tie access to their online communities to the subscription. Perhaps they need to offer access to the designers. I don't know. If they don't offer enough here, then they'll see lots of people subscribing for 1 month, downloading everything, and then walking away. (I suppose what they could do is delay access to the library until you have either been subscribed for X months, or until you sign up for a sub lasting those X months.)
(The equivalent with movies would be some sort of cinema pass, in addition to access to downloads. The equivalent with music would be discounts on concert tickets, or something similar.)
All that said, I don't think it's feasible. Disney will want the right to repackage and resell "Sleeping Beauty" and the rest every seven years, and it's very hard to fault them for wanting this (there's obviously a demand). However, if they refuse to change, they are going to have to accept that there's going to be some loss to piracy, and that that loss is probably going to increase over time. Furthermore, they should not be allowed to simply buy a 20-year extension to copyright every time "Steamboat Willie" is about to enter the Public Domain - this is a major factor in our IP laws not getting the revision that they need.