If you release a digital copy of your novel online, it's quite likely that at least a few people will copy it. However, there's also a pretty good chance it will attract more future customers.
Right, so if you provide a service you can charge what the market will bear but if you provide an art that happens to be convertible to digital form you need to get on your knees with your hat outstretched and beg for your income.
Do you people actually think about what you're saying?
You don't have a right to make profit, only to try.
In this case copyright only exists as an explicit tradeoff by society in order to gain other benefits. If those benefits can be obtained cheaper and/or without the limits imposed by copyright through other means, or if society decides the tradeoff is not worth it, then tough.
I personally don't think it's an unreasonable restriction until some way is figured out to compensate creators of digital media for their efforts that doesn't care about digital piracy. I do have a problem with some of the efforts that are being put in place to enforce these rules though, much in the same way I have a problem with the TSA.