Why send Moshe to give a dramatic speech if no one is listening?

Our Parsha begins with some of the most famous Psukim about Yetziat Mitzraym - the four terms used for the Redemption, which are the basis of the Four Cups we drink on Seder night. Yet, this dramatic speech Hashem sends Moshe to give, receives no response from Am Yisrael, they don't even listen because they are so occupied with the hard labor. This would seem like quite a failure, not the basis for Seder Night. Why would Hashem even send Moshe to give a speech Am Yisrael wouldn't care about?