Its pretty much like some of my music,Tv series,books, that almost no1 else has ever heard and I eventually make them at least check them and they love it.Then they tell their friends about it...And so on.
Just like when you buy something from store, you say to your friends "They are great" or "They suck", and suddenly store either lose 100+ customers, or get new 100+ customers.
Sure, if some Fps game gets 90+ metacritic, it will sell. But people are doupting Heavy rain, because its so unique.So demo is needed for mass market. For people like me, no.
Take my love, take my land..