Microsoft doesn't have one visual appearance across all its products now either. "Metro" isn't really a single visual style, it's more like a family of styles - Windows Phone "Metro" is different from Windows 8 "Metro" is different from Office "Metro" is different from VS2012 "Metro", etc. As for Windows 8 on various form factors, it's not a case of the same UI across multiple products as Windows 8 is a single product (whether you think it should be or not).