Piracy -> Friendly ways to buy -> Unfriendly ways to buy -> Piracy -> ...
Unfortunately, giving money back to writers involves hopping through piracy. At that point, a new, consumer-friendly service will sprout up. Everyone will use it.
Over time, the service will want to profit-maximize, and will adopt anti-consumer techniques. Leading people to go to Pirate Bay. Leading to friendly services.
Rinse, repeat.
There are other possibilities, such as people simply not writing as much anymore, or higher quality writers existing the market due to lack of sufficient return.
Similar thing happened with music, only rather than piracy, it landed on legal / free (e.g. Youtube). Youtube is just starting to do the consumer-unfriendly thing (but it's got a long ways to go before piracy comes out competitive).
Similar in books.
I'll mention: A lot of these are consumer-unfriendly in some ways (e.g. Netflix DRM), but friendly in others. $20/month for all the movies you can watch beats piracy.