Comparing Booth and Dalton -- Spoilers
Cliff Booth (Brad Pitt) is the real deal. He's the genuine embodiment of the John Wayne archetype that Rick Dalton (Leonardo DiCaprio) plays in his films, yet his life pales in comparison to that of Dalton's. He spends his days running errands for Dalton, constantly reassuring him that he's worthwhile, but lives in a trailer behind a drive-in while Dalton lives in luxury. Dalton got famous pretending to be Booth onscreen.
Throughout the film we see Booth effortlessly navigating dangerous situations. Whether he is casually leaping onto a rooftop to fix an antenna or talking smack to Bruce Lee then backing it up with his fists, he's a real life cowboy. His scene at Spahn Ranch is basically a real life Western. He shows up, confronts the band of outlaws, does what he says he going to do, then turns the tables on the punk who let the air out his tire. He's a bad ass and then some.
Meanwhile, Dalton is wrought with indecision and insecurity, and only shines in a pretend Western. He has to dig deep and really channel a character, and focus on the fact that he's acting. He cries over the approval of an 8-year-old girl. After his scene, in which he's compared to another famously overwrought fellow, Hamlet, he basks in congratulations for being tough in the moment of fake danger.
Then comes the end, where Booth does all the fighting, gets stabbed, kills two of Manson's clan outright, and mortally wounds the third, who staggers into the pool and would have drowned anyway, when Dalton, in an over-the-top fake Hollywood manner, as opposed to Pitt doing it with his fists and his faithful dog, burns her to death with a flamethrower. And then, of course, Dalton is given all the credit. He ends up relating his heroic tale to Sharon Tate and her friends while Booth is being taken to the hospital, and the film ends with him being granted entrance to the New Hollywood that had previously shut him out, and leaving behind the Old Hollywood, and the best friend who gave him access to it.