If you’re still flummoxed as to how an ambitious double-feature release from Quentin Tarantino and Robert Rodriguez bombed at the box office, Tarantino has some thoughts on why Grindhouse landed with a thud. In the mid-2000s, after taking significant time off following the release of Jackie Brown, Tarantino was on something of a filmmaking tear. He completed and released the two-part epic Kill Bill, he served as a “special guest director” on Rodriguez’s Sin City, and he even directed an episode of the then-massively popular TV series CSI. So when word arrived that Tarantino …