Gradients as decoration look boss today. They looked cheap 30 to at least 20 years ago. Then they were forgotten and that made their return possible. They'll become unfashionable again. It's an eternal cycle.

Windows 98/ME and the Office versions of the same time are often blamed for making gradients seem boring and uncool. (Windows put a Gradient in every title bar and Office over-used them in all sort of other ways.) Microsoft was definitely an interesting contributor to both the fad at the time and the "gradients are boring" rejection a few years later because they seemed boring and uptight like an Office program.