Grindhouse (lack of) audience anticipation

Saw another trailer for GRINDHOUSE at the movies last night. This one has been available online since last month - the one wherein the narrator explains the concept of a "grindhouse" double bill to you.

For me, the most interesting thing was the audience reaction - or, more precisely, the lack of a reaction. This was just before a screening of 300, full of teen-age boys who had come pumped on adrenalin to enjoy so CGI slaughter, so you'd expect them to be on board for what GRINDHOUSE has to offer. Yet instead of wild screams of enthusiasm, all I heard was stony silence, interrupted by a brief chuckle at the silly sight of the chick with the rifle in her leg.

The Internets have been boosting this movie for months, but this lackluster audience response made me wonder whether the whole "grindhouse" concept is something that only flies with a handful of cult enthusiasts. Hollywood seems fond of making movies about topics that appeal only to people in Hollywood (movies about movies, like ED WOOD, etc). Could this be another example?