They're aware PC gamers "would willingly give us money," but don't want to risk diluting Destiny by overtaxing their team with PC, and so are focusing "right now" on consoles.
The Halo creator's PC past is rather spotty with the original making it to PC, and its sequel, but all further main entries barred from enjoyment on desktops.
For those who thought things would be different now that Bungie is out from under Microsoft Game Studios, you're going to have to wait a while longer yet it seems. "It’s a huge challenge to ship four platforms and a massive opportunity to reach a new audience," Eric Osborne told in an interview.
"We know there are a lot of people out there asking for PC and we know that there are a lot of gamers that would willingly give us money, but what we have to do is make sure we’re focused enough to bring a good experience to any platform that we ship on. What we 100 percent are not going to do is spread ourselves so thin that it negatively harms the other platforms. So right now we have the four platforms, which is a lot to focus on."
Destiny is an MMO project and the PC market is definitely bloated with those so it's not surprising Bungie would rather hit markets generally scarce on the MMO front, i.e. Xbox and PlayStation. Hopefully PC will be wooed eventually.
Destiny releases on Xbox 360, PS3, Xbox One and PS4 in Q1 2014.