Maybe it was for the people on the edge.
If you're not going to vaccinate your kids because autism, you're already ignoring a massive body of evidence that says vaccines don't cause autism. Why does one more piece of evidence in the 'shit to ignore' pile change anything? Let evolution take it's course I say. Edit* Bad mood disclaimer. Sociology is making me angry.
It's okay. It's perhaps a weak answer but a valid point that those who may have heard of the theory but not truly looked into it or decided to subscribe to it may be surprised or swayed by the study. Recent research seems more validating than old research. However, you have a point as well, in that if grants and money keep getting poured into expensive studies that prove what we already know, it can be frustrating and limit other, more innovative research.