I would argue that they do have a truly innovative design. The fact that it doesn't look new and challenging doesn't preclude that. They have a design that's nuanced in thousands of ways to improve their business. Their design is reminiscient of Victorian architecture, every last detail polished off until it was perfect. Having your business fine tuned to that amount of detail is not something most companies can claim.
"Without split-testing, your product tends to get prettier over time. With split-testing, it tends to get more effective." - Eric Ries