I will agree with you to an extent. Early on it was the imports leading the way in fuel economy, but the domestics soon caught on and started improving things to an extent.
I will also contend that a lot of the belief our fuel economy is worse because up until recently, SUV's were the hot thing going. Big, heavy and with V8's, they did not do so well whereas while the iimports had similar SUV's, there sales were more in the lines like the Camry and Accord and so on. So the perception I believe became well I drive this Camry and I get x miles per gallon can haul around not quite as many as you but I dont really need to vs. you drive that large SUV with one person and get measly x miles per gallon.
As well, keep in mind that auto makers are a business and as such they are going to do little more than they have to. The point to which is that they are not going to go out of their way to produce fuel efficient vehicles unless A.) They are mandated to do so from the government or B.) There is demand to do so. Until recently, neither had been true. Even with the gas prices going up as high as they were it wasnt until gas price eclipsed the $3/gal mark, maybe a little more, that SUV sales really began to fall off. What do you think that says to the auto makers? Clearly it states that we want our big, heavy, V8 gas guzzlers even if gas prices shoot up, but we have a limit and it appears it was found at the price point north of $3/gal.
Hopefully people attitudes are well cemented now and will maintain the demand for alternative energy sources and for more fuel efficient vehicles. We'll see I guess.