Einstein, although he was a genius of his time, and still even now smarter than most of our researchers, did not have the information that we have even now, only 70 years later. Who is to say that there will not be new information that contradicts what he says? Back before the age of exploration, it was widely accepted that the world was indeed flat, and they had convinced themselves it was true with their "evidence". Who is to say that this instance is wrong?
The great thing about science that it is not set in stone. People can create many different ideas and test different theories. I love science because it welcomes different ideas and test. If something tested many many years ago is proved to be wrong than science accepts the new theory with open arms. Science is always changing and always evolving to better society. Just like Darwin can be and has been proven wrong on certain theories, Einstein can also be proven wrong.