Jay-Z is one of pop music’s greatest mythmakers, and his most jealously guarded myth is the notion that what he does is effortless. You see this in his insistence on composing rhymes without pen and paper, his omnipresent yet offhand allusions to his own sales history, and his boasts of intentionally dumbing-down his raps to appeal to wider audiences.

For the release of this week’s “Magna Carta Holy Grail,” he’s added yet another audacious note to the myth. Thanks to a multimillion-dollar promotional deal with Samsung and a change in RIAA rules, the album will be certified platinum on the very day it hits record stores and iTunes. In other words, Jay-Z can now move a million copies of an album before he’s even released it.

Yet for the last few years, there has been a growing sense of desperation bubbling beneath the braggadocio. After the lukewarm embrace of 2006’s “Kingdom Come,” Jay quickly retreated to his most well-worn and seemingly exhausted subject, the drug trade, for the awkward film tie-in “American Gangster.” Follow-up “The Blueprint 3” betrayed hints of flop sweat as Jay endeavored to co-opt all the newest trends from a rap world that seemed ominously capable of getting along without him. And on 2011’s smash collaboration “Watch the Throne,” he leaned heavily on his onetime protege Kanye West, a rapper who, for all his many faults, has always displayed a willingness to test the boundaries of his art and the patience of his audience in ways Jay has rarely dared.

The best that can be said of “Magna Carta” is that much of this strain seems to have eased. The Jay that emerges on the album is calm, relaxed, imperious, an expert curator with no shortage of nice things to display. Appropriately, the album’s guest appearances are all drawn from the A-list, with Beyonce, Justin Timberlake and Rick Ross showing up throughout. Timbaland has production credits on 11 of the album’s 16 tracks (with the likes of Pharrell Williams and Hit-Boy handling the others) and there are at least five sinuous beats here that will still be heard thundering out of slow-moving Jeeps a year or so hence.

Yet the record is ultimately less than the sum of its parts, and despite a few poignant glimpses of Jay struggling to deal with his recent fatherhood, too much of the album is stymied by Jay’s unwillingness to evolve.

By casting his life story as an updated Horatio Alger tale — and his self-made success as a subversion of the music industry’s shameful exploitation of black artists — Jay has always managed to turn his own rapacious wealth accumulation into a cause worth rooting for. This a difficult trick to pull off, however, and it’s one that’s becoming increasingly unsupportable. No longer content with name-checking fine wines and designer clothes, Jay spends an entire song here bragging about his fine art collection, though his only interest in great paintings appears to be the fact that he can afford them. “Somewhere in America” starts off with promise to be an incisive critique of upper-class hostility toward new money (especially when that money is wielded by people of color), yet by the end Jay mostly just seems frustrated with his local homeowners association.

Of course, Jay is too intellectually restless to give us an album without some surprising twists. He quotes Nirvana, R.E.M. and Billie Holiday, and takes potshots at Miley Cyrus, Scott Boras and Harry Belafonte. The album’s samples draw from such left-field sources as Gonjasufi’s “Nickels and Dimes” and Faye Dunaway’s “wire hangers” monologue from “Mommie Dearest.” Jean-Michel Basquiat receives no fewer than four shout-outs.

Yet these eccentricities are mostly just window-dressing, and even when he does venture into deeper territory, Jay is frustratingly eager to let himself off the hook. “Oceans” opens with a lovely melody from Frank Ocean, who ponders sitting on a yacht docked off the Ivory Coast, spilling champagne into the same waters that once bore the slave ships carrying his imprisoned ancestors. Jay follows suit at first, but by the second verse he’s become sufficiently distracted to remind us that his memoir “Decoded” recently topped the bestseller list. The Wu-Tang-infused “Heaven” seems poised to pose some intriguing eschatological questions, but once he’s asked them, Jay simply shrugs them off, rapping: “Question religion, question it all/Question existence until them questions is solved.” Well, it’s nice to have that matter settled.

But perhaps the problem isn’t so much the failure of Jay’s imagination as it is his inability to match these heavier topics with an elevated lyrical approach. Indeed, the most obvious issue with “Magna Carta,” as with Jay’s last few albums, is that he simply isn’t the rapper he once was.

While he was never hip-hop’s most accomplished wordsmith, Jay-Z’s ability to ease the slantest of rhymes and most jagged of sentence fragments into a buttery, casually musical flow was once second-to-none. In his late-’90s heyday, he could rhyme “R.I.C.O.,” “repo,” “vehicle” and “week ago” in the span of a single line and make it sound as natural as breathing. When he attempts similar tricks here, most egregiously in the opening lines of “Picasso Baby,” all that registers is the difficulty of forcing round words into square rhyme schemes.

“Magna Carta’s” lyrical nadir comes courtesy of song fragment “Versus,” in which Jay targets a strawman lesser rapper and mockingly compares “the truth in my verses, versus your metaphors about what your net worth is.” It’s a strange point to raise. No rapper in history has managed to rhyme about his stock portfolio as inventively and entertainingly as Jay-Z, yet so many of his most worthy peers stopped trying long ago. One of them even appears on the record as a reminder.

Midway through “Magna Carta,” Queens rapper Nas turns up to deliver a quick guest verse on the celebratory “BBC.” There’s always a frisson of excitement when these two appear on the same track, a pair of former rivals who still carry a torch for hip-hop’s ’90s golden age. Yet while Jay has tirelessly worked to maintain his hegemony in the decade since, Nas took a more difficult path, perpetually testing himself and experimenting, even at the risk of falling on his face. Full of hard-bitten wisdom, Nas’ “Life Is Good” was one of 2012‘s standout releases, tackling such topics as divorce, financial trouble, parenthood and the specter of cultural obsolescence with arresting honesty, and proving it’s perfectly possible for graying rappers to act their age and still produce exciting music.

There’s no reason to think Jay isn’t capable of aging just as gracefully, but to do so will require a dose of self-reflection, vulnerability and a willingness to fail. If “Magna Carta Holy Grail” is any indication, Jay-Z still has a lot of growing up to do.

Album Review: Jay-Z, ‘Magna Carta Holy Grail’

  • Production: (Roc-A-Fella, Roc Nation, Universal) Producers: Timbaland, Pharrell Williams, Swizz Beatz, The-Dream, Travis Scott, Hit-Boy, Boi-1da, Mike Dean, Jerome “J-Roc” Harmon, WondaGurl, Kyambo Joshua, Vinylz. Featuring: Jay-Z, Beyonce, Justin Timberlake, Nas, Rick Ross, Frank Ocean. Release date: July 9, 2013.