Sigh. PBS has announced this morning that the eight-week run of Season 4 of “Downton Abbey” will premiere in the U.S. on January 5, continuing on Sunday nights through the end of February. ITV has not yet announced the new season’s air dates in the U.K., but it will likely begin in September, as it did last year. So, why can’t PBS show “Downton Abbey” at the same time as ITV, or at least shortly thereafter? Vulture asked this question of a PBS executive early this year and was basically told that, well, they could air it in the fall, but they don’t want to, because they’ve always aired it in January, because there are competing priorities in the fall, and because, despite numerous viewer complaints about the long delay and subsequent spoilers, people watched anyway — “Downton Abbey” is by far the most-watched show in PBS history, with its Season 3 finale getting 50 percent more viewers than Season 2′s last episode. (Do NOT get me started on the Season 3 finale.) So, prop your feet up on a nice footstool and pour a cup of of tea; we’ve got a long wait in store. One wonders what the Dowager Countess would say; perhaps something about the pleasures of anticipation, and the absurdity of having one’s schedule dictated by others.