Well, whether there is or isn't more public domain stuff than not is rather irrelevant. Also irrelevant are the motivations of the TPB.
The fact of the matter is that anything digital has a marginal cost of $0, and thus will be subject to copying regardless of what anyone does. Until people making such items (and I'm a game programmer myself, so I've thought about this quite a bit) learn to monetize their products in a way that accounts for the fact that bits are inherently not-scarce, and thus not based on the economics of physical objects and scarcity, we will continue to have people bitching about copyright infringement.
I mean, yeah, it sucks, and we all still need to make some cash to feed ourselves, but I'd argue that we're doing that now. If you're an independent developer and find your stuff on torrent sites, why not ask the people downloading it why they didn't pay (without being super pissed off about it :P) and make the changes necessary (aside from just giving it away for free, although that could also work, with some other means of monetization tacked on) to include those potential customers too. And if the answer is "Didn't want to pay for it" well, guess what? They wouldn't have bought it any damned way.