Bethesda hasn't given up yet.
Thus far, there hasn't been any real news for Dawnguard and Hearthfire, but Pete Hines responded to some queries on his Twitter account regarding their issues with getting the DLC out on PS3.
I don't have any info on Hearthfire, Dawnguard, or DLC in general for PS3. We're still on it. Will share update when I have one.
So, nothing new there, but he also had this to say:
The performance isn't good enough in all cases. For most folks, it'd be fine. For some, it wouldn't be.
In response to being asked if he's at all worried about alienating the PS3 fan base, he said "I worry about anything that negatively affects any fan of any game on any platform. So, yes." It would seem that, at least for now, there won't be any news for a while regarding the DLC's release. However, there may still be some hope for players, as Bethesda stated "we've never blamed anyone or anything. It's our problem, and it's on us to solve it."
For the sake of all the PS3 players out there, here's hoping they can.