Perhaps I'm not fully appreciating just how big of a psychic scar the Sharon Tate murder is for some people, but the would-be catharsis of this film's final minutes feels particularly hollow to me. In Django Unchained and Inglourious Basterds, the ethos of the climactic orgies of destruction is clear: American slavery and the Holocaust were such incomprehensible horrors that the only fitting punishment for their perpetrators is to situate them in a Dantean inferno of cinematic violence. It is debatable whether Tarantino's perfervid bloodletting is justified even then (Basterds complexifies the audience's relationship to the violence in constructive ways; Django doesn't, really), but Tarantino at least contextualizes it effectively. Once Upon a Time ... in Hollywood, however, simply takes it for granted that the audience is itching to see three "fuckin' hippies," as Rick Dalton (Leonardo DiCaprio) labels the killers from the Manson family, dispatched as gruesomely as possible. Maybe some viewers were. I wasn't, though, and nothing I saw onscreen earned the gleeful brutality or the all-is-well happy ending. One may well wonder about the Manson family's other victims; Gary Hinman and Leno LaBianca, not being mythic Hollywood figures, apparently weren't important enough to merit their own revisionist salvation.
Of course, Tarantino doesn't intend for his film to be read so literally. Margot Robbie's "Sharon Tate" isn't actually Sharon Tate but rather a synecdoche for a bygone era of Hollywood that we (or Quentin, at any rate) nostalgically long for. Once Upon a Time aims not to provide some after-the-fact justice for real human beings but to allow us to visit an imaginary reality where its version of Hollywood doesn't get despoiled by marauding philistines. Sharon Tate doesn't have to die; Rick Dalton doesn't have to fade into irrelevance, supplanted by the young and flashy. They can live forever in Tarantino's snowglobe Hollywood, enjoying a heaven of sorts (signaled by the God's-eye final shot) at that late-night party at Cielo Drive.
Does Once Upon a Time actually succeed in selling this fairy tale, though? Paradoxically, the film's greatest virtue is also what destabilizes it. This is easily Tarantino's most grounded film. Rick Dalton's professional insecurity and fears about his future, Cliff Booth's (Brad Pitt) failing claim on Dalton's friendship and patronage, the lovingly shot montage of neon lights flickering to life along the Sunset Strip—these elements situate us in a reality that bears little resemblance to the pastiche-laden cinephile playground that we've become so used to seeing in Tarantino's other films. It's a breath of fresh air, honestly. It's also on a completely different planet than the scene in which Dalton uses a flamethrower to barbecue a blood-drenched, screeching gunwoman flailing around in his backyard swimming pool.
For Tarantino, the myth of Hollywood and the reality are inextricable. Sharon Tate is both a flesh-and-blood woman and a representation of the ideal Hollywood. This is self-evident to him. Judging by Once Upon a Time ... in Hollywood, he doesn't see a disconnect between the grounded human drama and the fairy tale. In avenging Tate's murder, rewriting her sad fate, he is rewriting the history of an entire era. Those who resonate with this perspective will experience Once Upon a Time as a balm. Those who don't will likely experience Tarantino's vision as a half-formed desire to be reconciled to loss—an echo without a source.