They’ve been less than inspiring for some time.
Nothing has changed in the look for a few decades.
Stagnant. Even Windows has a a new look since Windows 8 plus you can customize Windows by using 3rd party software like the following:
Wincustomize
https://www.wincustomize.com/explore/windowblinds
Stardock
https://www.stardock.com/products
Winaero - Free, small and useful software for Windows
https://winaero.com
WindowBlinds
https://www.stardock.com/products/windowblinds
How to Install Custom Themes and Visual Styles in Windows
https://www.howtogeek.com/168270/how-to-install-custom-themes-and-visual-styles-in-windows/