I have to seriously disagree with you Reelya. Purchasing a game should absolutely not be the only hurdle one has in seeing it the whole way through. Though this is largely genre-dependent, I think the onus should lie on the person purchasing the game doing their research over it landing on the developer to make it all inclusive. That mindset has lead to the stagnation in gaming we're seeing, as no one wants to risk innovation. I really hate what this mentality has done to MMO's because since the inception of MUDs, the genre was defined by difficult gameplay which required groups of people and socialization which now is no longer the case because of the "I pay my $15 a month too" mentality, and we can actively see exactly what that's done to the prime example that is World of Warcraft. There is no longer the carrot on the stick to strive for.
I used to argue this with people, it'd be ridiculous going into a game like Mario and demanding MMORPG features, yet for some reason it's perfectly acceptable to go into a genre which was defined by it's hardcore and social nature and to demand that it become more singleplayer and console focused, and since that "casualization" has started, we've got a measurable decline in a game that topped at 12-13 million active subscribers that now has dropped so low that they wont even report the numbers now. The casual mindset states that this is where the money was at, but the empirical data says otherwise.