It's a characteristic of America since its founding to venerate the past over the present. In novels of Fenimore Cooper, set in the 1750's to 1820's, the American forest of 1699 and 1730, was a vast, pristine natural, God-blessed universe. Civilization is seen as corrupting force (as in "Adventures of Huckleberry Finn"). In "The Great Gatsby," the final vision is of an America of vast promise corrupted by the present (1922 in the book). Similarly, most young adult find the cartoons of their youth more amusing and precious than the current cartoons: Inspector Gadget or Sponge Bob is better than whatever is on now.
This is to say that viewers' judgments are skewed by perspective. There is a prejudice for the past. The teens of 2019 are seen in 2019 as less polite and intelligent than the teens of 2014 not because they are, in fact, inferior in those ways but because of the American tendency to romanticize and glorify what is no longer here. The past remains inviolate. It cannot be experienced as it was, and its flaws become buried; but it s judged with contemporary immediacy.
This may be more than an American phenomenon. In the first book of Homer's Odyssey Athena tells Odysseus's son Telemakhos "the son is rare who measure up to his father." The past may hang over us always as an ideal. This idea plays out in large and small ways.