An assumption is not knowledge, and an interested party isn't going to dismiss a potential exclusive just because it failed its crowdfunding goal -- there's more granular data to observe than just "This game didn't hit $x." Take Flying Hamster 2, for instance, which secured external funding despite a depressing Kickstarter campaign.
Considering the mountain of shit The Chinese Room got from PC gamers over Dear Esther and A Machine for Pigs (walking simulator, pretentious, not a game, not as good as The Dark Descent etc.), maybe they're happy taking some investment dosh from Sony rather than rely on the fickle goodwill of gamers. I'm no champion of buying up exclusives but this might be a case of the Chinese Room simply taking an easier route for, you know, their own convenience and sanity.