Yes, I agree completely with this. For example, when the Xbox 360 first came out, almost every new game had a demo. I purchased many games because I liked their demo. I seldom see free demos any more. I have also purchased games on Steam after finding a demo, but they are harder to find too. I can definitely see the lack of demos being an incentive to try a pirated version of a game. It seems that the quality of a lot of newer games has gone down lately, so I can't blame people for being extra cautious.The lack of demos and real, accurate and honest previews is a genuine problem.
or I'm deathly afraid of my PC catching a virus from a hacked game
, a demo would be something I'm more likely to download than a hacked game. But, I suppose a game company could save themselves work by just assuming that the pirates will provide the "demos" for them. 