I buy games, probably too many really including ANNO 2070 which I played for like 10 minutes before uninstalling. Anyway even though I do buy games, especially ones I want multiplayer for, I have also downloaded games that ive gone on to play and not purchase/ games that I didnt like and uninstalled.
That makes me a pirate, although I do spend a fair chunk on PC games each year. I would assume (quite correctly) that at least 75% of PC gamers on these boards have downloaded a PC game to either try it or keep it..... and even if you then buy that game or other games, you are still a pirate as you are aquiring it without paying originally.
Id say a way around it is to release the full game as a free download... and then have the game stop and force you to enter a purchased key. OOTP has something similar, you get like 6 months full game iirc and then it will stop (6 months of the season that means) and to progress or start a new season you have to have a key.
Why dont more companies do that, do it via Steam so you have that additional protection, but release it free... you will get 'x' more people downloading it anyway to try it and then if they want to play it fully, they will then purchase.
It cant be cost effective to do that, but it seems like an easy way to appease customers whilst also accessing more customers and then offering a simple purchase route should the game be good. Quality would then be expected on release and I think everyone would benefit.