I don't blame the government. They have forced pollution controls over my lifetime that converted Los Angeles from a smoggy hell hole to a pretty clean atmosphere. I mostly blame the manufacturers for a bit of foot dragging. US manufacturers have been following (the Japanese) rather than leading. I blame the vehicle owners for not embracing the more efficient vehicles sooner. I think Detroit is in such big trouble because US car manufacturers didn't design for high gas mileage until the Japanese and Korean companies came on strong.