No. Because the toolbar and other window elements ARE ALSO CONTENT. This is what Apple and others are not getting.
BTW, this is also why it was stupid UI design to remove coloring from the sidebar. The Sidebar is content. This is why it was stupid UI design to remove coloring from the Mail sidebar. The sidebar is content. This is why it's stupid to flatten the traffic light buttons. They are content. This is why it is stupid to overly simplify icons. Icons are content (they communicate information to the user).
Everything on your screen is content. Good UI understands this and understands the concept of tiered content and contextual content. This is why translucency is bad UI. It makes the least important content (your wallpaper) primary content by drawing the eye and focus of your attention to it.
Good UI uses shape, color, and depth to let the user easily move between his different tiers of content.
Oh, and to all you people dissing skeumorphism, you are out of touch. Skeumorphism isn't about making computers easier to use for neophytes, it's about accommodating the hard wiring of our brains programmed through the fact that our entire lives are spent in a three-dimensional world of physical objects. You make a button look like a button because in the physical world people see and press buttons. Thus, when they see something that looks like a button, they immediately and instinctively know what it's purpose is; they don't have to waste effort identifying and processing the image. Throw a flat white rectangle up and now users have to spend conscious effort to parse the information. Forstall went a bit far with skeumorphism, to where it became a negative impact on usability, but Ive, with his wholesale abandonment of it is worse.
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You mean until a security issue comes up and the patch is to upgrade to Yosemite.