In its second season, “The Gilded Age” — Julian Fellowes’s peculiar attempt to channel the themes of Edith Wharton in the key of “Downton Abbey” — abandons lofty and literary ambitions and settles for being the soapier, sillier project it always was. This makes it a massive improvement over the muddled and strangely anticlimactic first season, which set up several promising storylines and then inexplicably failed to deliver on any of them. “The Gilded Age” knows itself now: This is a series about the new rich spending outrageously to bring down social barriers the American aristocracy tried to keep in place. There’s a blistering simplicity to that, and to Bertha Russell (Carrie Coon), the show’s real heroine, whose only wish is to achieve an uncomplicated form of punitive social supremacy, and who acquires absolutely no additional traits or dimensions in the new season.