Nick Bradbury, developer of TopStyle, HomeSite and FeedDemon, did a test to see how many were using warez'd versions of TopStyle or more acurately how many ran TopStyle once. Now the one big mosterously gigantic hole in his logic, how many first runers would have been actual purchasers? I'm sure that small developer software sales are lost, but I'm betting that the amount is actually much smaller than anyone would expect.
The same situation applies to movies and music online. Sure there is rampent downloading. But how many would have been a purchase absent of the downloading option? Again I'm betting much smaller than anyone would expect.
Eventually that situation will change. Sometime around when the current highschoolers are running things. Just like the American Factory Worker, digital content creators are going to lose those nice fat cushy margins. So you have a choice come up with a new buisness model for getting money into the hands of digital creators. Digital rights management and laws that don't mirror the reality of the users wishes just don't cut it.