Knew this would come up, and it's complete bollocks. Maybe that's what you do, and you'd like to believe that every other pirate does it too, but it's just not true for the vast majority of them. They already have the game, so why do they need to buy it? If they want to try and justify it to themselves, they can say they didn't like parts of it and never pay anything, but they could have still had many hours of enjoyment out if it and paid absolutely nothing.
Then don't. Wait for a reviewer you trust to give you their opinion, wait for a demo if there is one planned, or wait till it's on sale.
When Mass Effect came out, my financial situation was terrible. I was in thousands of pounds worth of debt and could barely afford to eat, so needless to say, I didn't buy it. By the time I dragged myself out of debt and had a little disposable income, Mass Effect was £5 on Steam and I snapped it up right away. Waiting didn't hurt me, infact I got it for an absolute bargain, while still contributing to the developers.
Read up on it before you buy it. Within a week of a game's release, you'll have information on how good it is, how long it is, what the performance is like, etc, from many different sources. If it turns out to be short, but still sounds good, wait til it comes down in price. Nothing says you have to buy it on the release day and waiting won't kill you.
Anyway, all I get from your posts is that you are trying to justify to yourself and others that you're not doing anything wrong. Well, you are, and there's no question about it. Complain about the state of the gaming industry all you want, but the fact is you're still playing the games they're producing and not giving anything back and it's making things worse, not better. The only people who don't suffer are selfish pirates like yourself, but if you gave a damn about anyone but yourself, you wouldn't be a pirate in the first place.