Hollywood’s clean little secret is that many people in the industry are not, at least by natural inclination, the utter shlockmeisters that their output would suggest. They are often cultivated, tasteful, hard-working craftsmen sometimes pained by the trashiness the public demands from them.

Over the last decade, the animated Shrek franchise about a green ogre in a tawdry fairy tale land has offered perhaps the most flagrant example of What the People Want (and Deserve to Get, Good and Hard). Yet, in Shrek Forever After, its latest (and likely last) installment, the filmmakers have moved in a surprising new direction.

The typical billion-dollar box office property, such as the Lord of the Rings, Harry Potter, or Spider-Man series, is based on an elaborate preexisting work whose integrity is jealously guarded by fanboys. In contrast, the 2001 Shrek was a surprise hit derived merely from a 32-page bedtime book by William Steig, allowing the franchise to become a tabula rasa pandering to median 21st century tastes.

The first Shrek had evolved into a poison pen letter from DreamWorks executive Jeffrey Katzenberg, the former Disney studio head during its Beauty and the Beast silver age, to his ex-boss Michael Eisner. Shrek‘s villain, Lord Farquaad, was modeled on Eisner, who had tried to cheat Katzenberg out of his share of Disney profits (eventually settling for, reportedly, $280 million).

You might have expected that the audience for a family film would have either been oblivious to or alienated by this backstory of Hollywood venality. Instead, they were galvanized.

The meta-joke of Shrek was how DreamWorks”€™ crudely animated versions of public domain Disney characters (such as three small pigs or a wooden boy) tiptoed right up to but didn”€™t quite violate Disney’s notoriously well-defended copyrights. It’s remarkable that the public now gets intellectual property humor, but also a little depressing.

Katzenberg had previously overseen the revitalization of Disney feature cartoons. His key decision had been to follow the suggestion of lyricist Howard Ashman, who died of AIDS in 1991, that they envision The Little Mermaid as an animated Broadway musical.

Disney subsequently made billions off the daddy’s little princess market, but alienated older boys in the process. (Although modern Americans love to congratulate themselves on their urbane tolerance, elementary school children have come to use “gay” as an all-purpose insult.) Katzenberg strove to occupy the boys’ animated feature niche by positioning Shrek as the anti-princess movie.

The original Shrek was good, nasty fun, with Eddie Murphy’s performance as a talking donkey one of the funniest instances of comic relief in the history of animated features. But Cameron Diaz (Charlie’s Angels) was cast as the princess merely because she was the blonde of the moment, and Mike Myers (Austin Powers)—who is a sketch comedian, not a leading man—was dull as the title monster.

Using movie stars as voice actors ought to be a waste of money because there are superlative voice talents available who can”€™t be screen stars because they don”€™t look like their voices sound. For example, the great cartoon slob Homer Simpson is wonderfully voiced by Dan Castellaneta, a trim, prim yuppie.

Moreover, this cartoon fairy tale’s abhorrence for all that girly stuff, like singing and dancing, meant that to fill up the time that would be taken up by songs in a classic Disney feature, the filmmakers deployed a lot of crud: fart jokes, disposable pop-culture references, and industry insider snark.

With no further source material to draw upon for the 2004 sequel Shrek 2, the DreamWorks team tapped the collective id of the American public, concocting one of the most noxious movies of the decade: a stew of sex jokes for nine-year-olds, Rodeo Drive consumer cravings, and Inside Hollywood shtick. Meanwhile, the three stars formed a cartel who demanded (and received) $10 million each for the easy gig of voice acting, even though Myers and Diaz were eminently replaceable.

Not surprisingly, the public adored all this hoo-ha. 2004’s Shrek 2 was a colossal four-quadrant smash with young and old, male and female, taking in $441 million at the domestic box office.

Shrek the Third grossed a mere $323 million, however. The inevitability of the demise of the franchise appears to have liberated the filmmakers in their last trip to the well to make a movie they won”€™t be ashamed to someday show their grandchildren. Thus, Shrek Forever After is an unexpectedly sweet little film.

There’s nothing original in it, but it borrows from the best: It’s a Wonderful Life, The Wizard of Oz, and Back to the Future. And, instead of hiring, say, Adam Sandler to voice the new villain Rumpelstiltskin, they just let animator Walt Dohrn play his own character. He’s better than Sandler would have been.

Of course, the public is not pleased. Despite inflated 3D ticket prices, Shrek Forever After opened with a first weekend haul of $71 million, down more than $50 million from the forgettable third installment.