David Hockney: Domestic Scene, Los Angeles, 1963, oil on canvas, 60¼ inches square; at Tate Britain.

"David Hockney is one of the most popular and widely-recognized artists of our time," states the introductory wall text in Tate Britain's retrospective––though actually that's putting it mildly. In fact, Hockney is the best-known and most popular living artist in Britain today, which is why tickets for this exhibition are the fastest-selling in Tate's history. For non-British audiences, though, his unique status at home requires some unpacking. Part of it, naturally, involves the British obsession with class and the appeal of a Northern, working-class lad made good. But beyond that, as he approaches his eightieth year, Hockney has become the sort of cozy, establishment figure that in the UK habitually gets referred to, with simpering archness, as a "national treasure." He's one of the very few artists, for instance, whose creative exploits are considered newsworthy enough to make a newspaper's main section––even when he's simply producing colorful paintings of trees or country lanes. Or, perhaps, especially when he's painting trees or country lanes. For that, ultimately, is what Hockney has come to signify within British culture: the maintenance of traditional, figurative values, updated as inoffensively as possible. He's the nation's favorite "modern" artist, but in a nation that's never really been comfortable with the experimental nature of modernism.

And yet, the main thesis of this exhibition, as put forward by curators Chris Stephens and Andrew Wilson, is that Hockney is an intrinsically experimental artist, always shifting between different styles. And for the first half of his career, that's certainly true. The muddy, scribbly paintings he made as a student at the Royal College of Art pull all sorts of ideas together, often in a single piece, with thick, abstract flurries of paint combining with more Pop-oriented typographic or graffiti elements, and human forms veering between cartoonish homunculi and tremulous smears. Yet the most significant piece from this period is Tea Painting in an Illusionistic Style (1961), a shaped canvas depicting a Bacon-esque figure painted on a tea carton, that playfully anticipated the increasingly realist route he followed over the next two decades.

Initially, that tendency was tempered by a more whimsical, dreamlike approach. The works Hockney made after graduating in 1962 are some of the highlights of the show––still cheerily sketchy and insubstantial, with flattened, hieratic figures, but now offering single, semi-realized scenes: a friend standing next to a museum's Egyptian sculpture in The First Marriage (A Marriage of Styles I), 1962; one man soaping the back of another in the shower in Domestic Scene, Los Angeles (1963). Large areas of canvas are left raw, with only occasional objects picked out in detail, as if the works are content to give only a vague, indeterminate impression of what they could be. No wonder Hockney was opposed to the purity, the formal self-containment, of much abstract art of the time, and in fact several paintings satirically adopt Kenneth Noland-esque targets, incorporating them as figurative devices. Hockney sought a different sort of abstraction: the abstraction of visual quotation and pastiche, of sampling from the world's endless parade of imagery. It's an approach that climaxes after he moved to Los Angeles in the mid-'60s and began painting an almost comical array of Americanisms: desert cacti and lonesome highways, headdressed Indians and the Rocky Mountains––all in bright, sunshiny acrylic hues.

He produced his most compelling visions of American life, though, in the period that followed. Paintings such as Peter Getting Out of Nick's Pool (1966) and A Bigger Splash (1967) are among the most iconic works of the twentieth century, as Hockney proceeded to develop a sort of mythological Los Angeles, a realm of crisp blue skies and swimming pools and languorous sexuality, of life reduced to its simplest, sharpest schematics. Witness the perfect Vs of water in A Lawn Being Sprinkled or the rectilinear precision of Savings and Loan Building (both 1967). Indeed, it's fascinating to consider such pieces in terms of his ongoing dialogue with abstraction and formalism. The painstakingly painted spray in A Bigger Splash was a knowing parody of Abstract Expressionism's macho gesturalism. But at the same time, the border of unpainted canvas that Hockney often left emphasized the works' materiality, and prevented them from being read in purely illusionistic terms, as windows onto the world.

Any resistance to realism was soon overcome, though, with his move into huge double portraits, those impeccably rendered studies of famous friends and acquaintances of the late '60s and '70s. Impressive as the works are, it's hard not to read a slightly cloying note of self-regard concerning his accomplishments––both artistic and social. Still, there's one utterly astonishing piece from the period: Portrait of an Artist (Pool with Two Figures), 1972, which evokes Hockney's disintegrating relationship with his then partner, and ranks as an absolute masterpiece of sexual longing and unease. Indeed, it makes you wonder why the exhibition never addresses homosexual desire as a major theme in Hockney's work. The focus on him as a stylist is all well and good, but one of the truly radical things his paintings did was to help normalize homosexuality by portraying it in a domestic setting.

After this stage in the show, unfortunately, things go downhill. There's a room of drawings that showcases Hockney's undeniable virtuosic skill but feels rather like it's intended to make the case for verisimilitude. Then there are his photography experiments from the early '80s, where a single subject is spread across multiple, collaged images. Only a couple of the earliest Polaroid grids, however, are really effective at producing the tessellated, fragmented impression that Hockney intended, and the technique soon becomes formulaic.

Even so, he essentially continues with this notion of destabilizing a single, monocular perspective for the next thirty years, exploring it in paintings of looming, warping California landscapes and weirdly folding LA interiors. The results are luridly intense, the shapes fantastic, yet it feels like he's simply taking familiar concepts from Cubism and Surrealism and jazzing them up a bit with modern, brighter colors. There's no attempt at social commentary anymore, no sense that art should be anything other than a visual exercise. It feels like a dead end. All he can do is make his paintings ever larger, using multiple, contiguous canvases. The technique is occasionally effective, when the view is the epic sweep of the Grand Canyon. But his vast depictions of the wooded Yorkshire Wolds, following his return to Britain in 2004, for all their fizzy hues and gargantuan, room-size scale, seem facile and uninspired.

The same could be said of his much-lauded iPad "paintings" from the past few years, which attract the biggest crowds in the show. The subject matter of these still lifes, portraits, and landscapes may be traditional, goes the standard argument, but Hockney's use of new technology is inherently radical. Yet of all the works, these are perhaps the most conservative. Presented as time-based video-pictures, so that you can see the images being progressively formed through digital brushstrokes, the works are a way of fetishizing the invisible hand of the artist, reveling in his magisterial touch. It's such a depressingly archaic notion of what art is about, a way of offering something familiar and reassuring in a rapidly changing world. The younger Hockney, who embraced uncertainty and indeterminacy, would be embarrassed.