I don't think the mainstream audience "got" 4/5 of Pulp Fiction, as even LESS of Jackie Brown but both flicks were in the same vein. Both were to subtle and coy most Americans who lack enough flavor and whit to "get it"
I think what Tarantino did over the past years which killed it was he made "it" less subtle and too obvious as others have pointed out. For example, we never found out what the fuck was in Marsellas' fucking brief-case, something which most Americans either were probably pissed off about or even really didn't notice
