I disagree, Sony knows that they have a good amount of the Hardcore gaming base. Which is why they gave up time in their conference to show this. This game is really only known to the hardcore online gaming community. Sony's backing that was clarified was they would cover marketing cost, and the port to the PS4 version. Sony could have still funded the marketing with the promise of exclusive marketing rights/ timed exclusive Additional content.
It would have been no different than previous marketing deals with AAA games i.e. Destiny, Diablo, and upcoming titles COD black Ops3, Star Wars Battlefront, etc.. Those games came to multiple consoles, but Sony still footed the cost to market those.
Exclusivity is a nice thing, but for a game that needs all the help it can get. Yu Suzuki went about it the worst way possible.
Edit: As far as MS funding this, and not jumping at the chance. So what? Sony is not funding it either, even SEGA is not funding their own IP. Bringing up MS as if they dropped the ball is silly, Nobody wants to fund this, hence why it went to KS. At this point, Yu Suzuki would have been better off turning it into a digital novel, If he really wants this story to be told.