The unusual narrative structure of A Little Life and why authors should show, not tell

Started reading Hanya Yanagihara's much-acclaimed novel A Little Life - yet another novel about young, ambitious people in New York, college friends now trying to make it in the business or arts world, etc. How many times can this tale be told? There is no doubt a certain narcissism or hall-of-mirrors effect going on here - writers lives in NY because other writers and agents and editors and publishers live in NY and so novels get written about NY and novels about NY get published (in NY) because who doesn't enjoy reading about themselves? Ok, in any event - though HY is covering some familiar ground here, how's this novel? Well, it's long - I read nearly 70 pages last night, and that's less than 10 percent of novel and I feel I'm just now starting to get a handle on the characters. The story centers on 4 mid-20s guys, the college friends: JB, Willem, Jude, and Malcolm. It takes nearly 50 pages or so to start to get them straight, but I'm getting there. What's truly unusual and a bit puzzling about this novel is that, 70+ pages in, the novel is entirely made up of back story: HY tells us in an interwoven fashion, the back story on each of the four, with passages from their time together in college, their childhoods, their housing situations in NYC, etc. There is no "foreground" to the novel, however; most novels would begin with some kind of action, problem, situation, conflict, or crisis, and then once the author establishes the narrative the author would begin to build in the back story, as needed. It's a very odd strategy to give only back story, because we are getting to know something about these people but not getting to see why we should care about them. My sense is HY is pulling her punches and will introduce some narrative tension down the road - she's working on a very large canvas here and knows she has time to let her story unfold in its due course - but she's in danger of losing readers (me) unless she gets with the fundamental rule of narrative: show, don't tell.