I do believe that original meanings can be almost completely lost to all but the likes of "us". One example is decimate. This word means, to nearly everyone speaking English, devastate or destroy. It's original meaning is the loss of every tenth, resulting in a 10% loss overall, a far cry from destruction. I agree that the concept can still be expressed, but probably not by using the original word, in many situations. Awesome has not tumbled nearly as far as decimate, however, mostly because the root word, awe is still widely recognized and used ("in awe") and retains the same general idea of its original meaning.