The question seems to me at best ingenuous and at worst paternalistic, ignoring in the first case the fact that such stories have always had a broad appeal, and subtly suggesting in the second that if it doesn’t contain sensationalistic story and spectacle, contemporary audiences (especially non-English ones) won’t get it. Yes, the hidebound class system depicted in Downton is alien to contemporary social mores; and yes, the series proceeds at an appropriately stately pace, with little in the way of lascivious storylines (Mary’s near-affair with the Turkish diplomat being the exception, sort of), and much harrumphing among both upstairs and downstairs about tradition and custom and the difference in kind between the aristocracy and everyone else.
But to wonder why this all appeals to contemporary audiences doesn’t give enough credit to contemporary audiences, who know a good story well told when they see it. There was much the same sort of pondering during the Jane Austen renaissance in the mid-90s, starting with the Colin Firth Pride and Prejudice and continuing with the adaptations of Emma, Sense and Sensibility, Persuasion, and Mansfield Park (which, had a production of Northanger Abbey been done, would have run the gamut of Austen’s corpus). Why, everyone asked at the time, is Jane Austen so popular again?
Theories advanced at the time tended to focus on nostalgia, a wistful desire for the certainties of a stately and stable class system; Generation X (remember them?), stuck in their dead-end jobs and aimless lifestyles, thought longingly of the calm certainty of Mr. Darcy or Emma Woodhouse’s lives. The appeal of Downton Abbey, it has been suggested, lies in both the revisitation of Austen-esque manners, but also the social ferment underlying the action as WWI starts to show the fault lines in the British class system and heralds the slow decline of the British Empire. In a recession-stricken time, it has been suggested, the discomfiture of the aristocracy and the new possibilities for social mobility resonate with audiences angry at the predations of Wall Street.
None of which I disagree with—certainly the waxing and waning of Austen and the periodic prominence of such series as Upstairs, Downstairs, The Jewel in the Crown, and Downton Abbey reflect shifts in the popular imagination—but it does seem a little overblown to me. The better considerations I have read do get around to the more important question, “why now?” as opposed to just “why?” but then the appeal of Downton Abbey seems self-evident after watching just one episode … it is extremely well written, well acted, and well produced, and makes one want to know what happens next.