This assumption is flawed. Downloading something doesn't necessarily mean you will actually get around to playing it. I've downloaded plenty of games that I never even got around to installing and just ended up deleting when I needed more free space. In addition, downloading has zero risk. Many people download stuff simply because they can, not because they value the things they download. For example, I've downloaded and watched many of Uwe Boll's films. Does that mean I'd ever pay a cent to watch them legally? Hell no. I downloaded them out of morbid curiosity and the knowledge that I wouldn't risk any money in the process.
The assumption isn't flawed, although the author would probably benefit from making a distinction between monetary value and utility (i.e. satisfaction derived from the consumption of goods and services).
People like yourself who download games or Uwe Boll movies or whatever, are doing so because you put some expected utility on whatever it is you download. IOW, you expect that at some point you will derive some satification from what you are downloading. This is why you would choose to download Uwe Boll movies instead of, say, a bunch of pirated Stephen King e-books.
Translating that into monetary value, assuming you leave your PC on for the purpose of downloading these things, you're expending electricity which in turn costs money (assuming you pay the bills). Even if it translates into mere pennies to download all these things, that's still pennies higher than everything else you choose not to download. So there is some monetary value placed on these items, however small.