It's because the values of capitalism by any means necessary to save money (i.e. complying with environmental regulation) is often prioritized in American culture above responsible capitalism. Not only that, but compared to other countries, the US is a society of convenience, they invented the drive through window (aka "drive-thru", haha) after all. And public transportation has been much easier in every country I've been to besides the US, where in the US, it's difficult even in a city with millions like Los Angeles. Last but certainly not least, the average American omni's diet seems to be much heavier on meat than, say, the average European omni's.
Acknowledging not only the existence of environmental destruction but also how the average American is contributing to it would require everyone, or everyone who has been of the mentality that has made them part of the problem and not of the solution, to rethink the whole way they live! So for many, it's easier to sweep the problem under the carpet than it is to change and adapt.
And tough to say if it will change soon, and how. It could go one of 2 ways, either enough pressure is put on the US from other countries to get them to change their act, or pollution will get bad enough to the point where it kills Americans and everyone else on a large scale, therefore forcing them to change their act for the sake of survival.
For the record, my location is the Netherlands, but I am American, and I've travelled to almost every continent now, so I've been able to compare mentalities pretty well. And the world could definitely use the Dutch mentality which, by and large, is much more aware of the cause and effect relationship of our actions than the American one is.
