Freddie Gibbs rhymes the way he talks: quickly and cleanly, with little sentimentality or exaggeration. Photograph by Evan Hurd

Weighing in early on what academics call “periodization” is a dicey proposition. If you try to locate the moment of a major paradigm shift, in the moment, perhaps by calling your album “Hip Hop Is Dead,” as Nas did in 2006, you’re slipping into weatherman territory. Will it rain tomorrow? Will another great rap album pop up? The life spans of genres and art forms are best perceived from the distance of ten or twenty years, if not more. With that in mind, I still suspect that Nas—along with a thousand bloggers—was not fretting needlessly.

If I had to pick a year for hip-hop’s demise, though, I would choose 2009, not 2006. Jay-Z’s new album, “The Blueprint 3,” and some self-released mixtapes by Freddie Gibbs are demonstrating, in almost opposite ways, that hip-hop is no longer the avant-garde, or even the timekeeper, for pop music. Hip-hop has relinquished the controls and splintered into a variety of forms. The top spot is not a particularly safe perch, and every vital genre eventually finds shelter lower down, with an organic audience, or moves horizontally into combination with other, sturdier forms. Disco, it turns out, is always a good default move.

Hip-hop, a spinoff from New York City’s early disco culture, has been a commercial proposition since the release of “Rapper’s Delight,” in 1979. That’s thirty years, a long time for any genre. If you want to be conservative and decide that mainstream cultural relevance kicked in toward the end of the eighties, with New York’s golden age and the quick follow-up of gangsta rap, the wildly popular genre from Los Angeles, that still leaves twenty years of cultural impact. This may be a fine time for hip-hop to atomize. The original form has done an awful lot of work.

“The Blueprint 3” falls in line with other recent mass-market successes in hip-hop. Compare it to Kanye West’s “Glow in the Dark” tour, or Kid Cudi’s breakout hit “Day ’n’ Nite,” and you will notice that this is hip-hop by virtue of rapping more than sound. The tempos and sonics of disco’s various children—techno, rave, whatever your particular neighborhood made of a four-on-the-floor thump—are slowly replacing hip-hop’s blues-based swing. It doesn’t matter if you’re talking about the rudimentary digital sound of New Orleans bounce or the crusty samples of New York hip-hop: this music wants to swing and syncopate. On major commercial releases, this impulse is giving way to a European pulse, simpler and faster and more explicitly designed for clubs.

A mildly entertaining patchwork of styles, anchored by lots of guest singers and rappers, “The Blueprint 3” is only tenuously connected to Jay-Z’s best work, and a patient listener will have to accept that. Gone are the autumnal poise and the tightly nested meanings, verses delivered with the bravado of someone who knows he could go all night but will bow out early to appear deceptively human. The new Jay-Z is a relaxed impresario, a Macher with A-list friends making safe choices. On the single “D.O.A. (Death of Auto-Tune),” Jay-Z mentions rappers that he previously overshadowed, an acknowledgment, perhaps, of a shift in hierarchy: “This shit need a verse from Jeezy, I might send this to the mixtape Weezy.” The latter is a reference to Lil Wayne, who publicly claimed the title of “greatest rapper alive,” while also stipulating that it used to belong to Jay-Z. Wayne was right, for a while, and then went weirdly silent, save for a few odd rock tracks. Wayne’s 2008 release, “Tha Carter III,” which included “A Milli,” a thick, psychedelic ramble tied to a thin, metronomic canter, was the year’s biggest-selling album—and probably the last moment when hip-hop was both popular and improbably weird.

“The Blueprint 3” features nothing as startling or vital as “A Milli.” (Jay-Z albums were once routinely loaded with three or four such songs.) The only tune that interrupted the summer flow of Michael Jackson songs in my Brooklyn neighborhood—not far from where Jay-Z grew up—was “D.O.A.,” a bit of a stylistic throwback, using a generous sample of an obscure 1970 rock record. It sounds more like vintage nineties Jay-Z, and it’s the only track in that mold. The rest of the album veers toward a pop median, giving synthesizers and R. & B. singers the last say. For “Run This Town,” that means Rihanna has to tackle a dreary and aimless melody that could be saved only by someone with a surplus of persona. (Mary J. Blige and Nina Simone come to mind.) On “Empire State of Mind,” Alicia Keys improves matters significantly, sending her voice high and strong: “Let’s hear it for New York! ” Why not?

The album begins, though, with “What We Talkin’ About,” which sounds like a cover of a slow Italian disco number from the seventies with a particularly tuneless chorus. “Young Forever” is genuinely European, a flat-footed remake of “Forever Young” by the German synth-pop band Alphaville. “Off That,” Jay-Z’s duet with the young rapper of the moment, the genial and deft Drake, works over a brisk computerized bubble that doesn’t necessarily sound as if it needed any rapping. None of the beats here are subpar, and Jay-Z is too smart to be boring, but there are few verses you’ll walk around repeating (unlike “The Black Album,” from 2003, which read like an alternate Bartlett’s, all pith and punch lines), and the music simply confirms that Jay-Z knows what’s happening in pop, not that he necessarily belongs there.

Other rappers will likely ride this new wave of club beats better than Jay-Z, but they have yet to emerge. It won’t be Kid Cudi, whose singsongy mumble does nothing to save “Already Home,” a sluggish number on “The Blueprint 3,” and whose début album, “Man on the Moon; The End of the Day,” manages to be both distracted and ill-tempered.

As the marquee names nudge rap into its transitional, synthetic phase, a host of traditionalists are doing strong work in well-known older styles. This movement reminds me of metal and jazz, areas where artists work in a larger number of established subgenres that do small but consistent business with loyal audiences. The claim to shock is traded in favor of a reliable form and a reliable following.

Raekwon, one of the Wu-Tang Clan’s core members, just released “Only Built 4 Cuban Linx . . . Pt. II,” the follow-up to his 1995 début, “Only Built 4 Cuban Linx . . . ” It’s a sequel few thought would come and fewer thought would be any good. (Imagine if “Chinese Democracy” had been as good as “Appetite for Destruction.”) Raekwon has drifted between uninspired beats and retreads since the nineties. He seems to have found his voice by simply returning to where he started. “Cuban Linx II” sounds like an old Wu-Tang record: scraggly samples from soul records and rapid, gnomic bundles of rhymes about drug-selling and agitated encounters. Almost every skit involving Raekwon or his partner, Ghostface Killah, involves somebody yelling at somebody else. This is the Wu-Tang vision of living in the projects, “The Wire” before there was “The Wire.” Whether or not it really represents life as Raekwon and his bandmates know it isn’t relevant; this is the life that they know how to describe, and there’s an urgency here that’s entirely missing from the recent work of artists like Jay-Z and Kid Cudi.