The PC has largely stayed out of the cold console war between Xbox and PlayStation: a battle over gamers' wallets that sees games and downloadable content alike being tied to absurd exclusivity deals. Thanks to those deals, however, we're often subjected to consumer-unfriendly delays that effectively punish people for buying for the 'wrong' platform.
It's nice to have some confirmation that Fallout 4 won't feature any of that shenanigans. It will have some shenanigans—a season pass—but all of the DLC will arrive at the same time, regardless of which platform you happen to be playing on.
Bethesda's Pete Hines confirmed as much on Twitter, in response to 'XxThe5sGuyxX', who asked "Will Dlc come to Xbox One first or will they release at about the same time?"
Hines replied that "we aren't doing a DLC exclusive with anyone". Which is a nice thing to hear.
Fallout 3's expansions launched on Xbox 360 and PC via *spits* Games for Windows Live, a few months before they appeared on PS3. Things levelled out over the course of Fallout: New Vegas' DLC schedule, though Bethesda returned to the bad old days for Skyrim's various expansions. We had to wait several weeks for those to migrate from the Xbox 360, to PC and PS3.