Hmm. I disagree. As long as there are materials, as long as humans have a sense of aesthetics, and as long as we have physical fingers, we'll want something comforting. Something familiar where nothing is. That's important to us, intrinsically. It assists with comprehension. And it's also part of why we name everything we come across.
If you can tie it to the physical, it can be understood. If it can be understood, it can be used.
Indeed. But if you look at the mobile form factor skeumorphism is much less critical now. iPad and so on lovely, but for mobile most people are so used to the tap and slide patterns (remember iPhone 1 was not ~very~ skeumorphic) there's a lot of flexibility now. As in for 4" one need not go crazy making a header that looks like leather, paper, or leaf, and so on. Still, where possible skeumorphic is quite tasteful, in my view.