Quantum v Relativity

This is partially a response to Tara's post, but also an elaboration on my post last Sunday. From the beginning of Relativity, I noted that Einstein is following several of Newton's for philosophizing in attempting to keep his theories unified, harmonious, simple, and correct. In ch. 21 he addresses the foundations of classical mechanics and special relativity and as Tara, a believe correctly notes, resolves nothing. This is likely part of the basis for the two fold hypothesis of current physics, maintaining quantum mechanics on the small scale and relativity on the larger scale. Stephen Hawking has proposed in his book that both are likely wrong in their own way, and maintains that a unified theory of physics should be sought after. Newton would likely maintain this same belief, especially because of his insistence on harmony in all things. He, of all people, would not have accepted two contradictory theories of physics. So I wonder if with the several hundreds of years of theorizing since Newton if we have taken a step backwards in our human quest to simply nature.