"Matt Engstrom, director of monitoring products at Shure, admits there is evidence that suggests transducers in larger headphones can experience burn-in, and that this could, in theory, produce different sound over time."

I would agree that IEMs (the E1 is an IEM which is different than headphones) don't require burn in and the signiture change is not noticable. But even your evidence against burn in doesn't dispute headphones with large drivers (traditionally audiphile grade headphones) have sound signiture that alter with use.

Thank you for providing more evidence for my point and against yours. I would reccomend reading past the title next time.