Fiction has “lost its ambition,” Sam Kahn says in a recent piece on “Castalia,” his popular newsletter. “It’s lost its centrality to the culture.” I agree with the broad thrust, with an exception I’ll get to later. Kahn is thoughtful about this, and I happily chewed over the topic with him recently on my podcast. And yet. This point, expressed in various ways, has been out there for a long time.