In order for user interfaces to be able to move away from skeuomorphic techniques one has to consider the willingness of the audience. Web design has been a great test bed for this very things. For many years using anything beyond the base set of html controls + date pickers was considered largely pointless, as businesses needed interfaces that took very little training. As the web evolved into a more entertainment oriented place, technologies like DHTML, Flash, and Javascript allowed designers to experiment with things like sliders, switches, and different types of paging. Apple capitalized on this by taking the best new controls created and built them into the iPhone, which worked so well it gave designers a much larger base set to work with.
In short, introducing stripped down UI's or new controls tend not to succeed when they are forced or simply swapped in because they are "more efficient". They are versioned in for a reason, because people need time to adapt to change.
As for "useless areas or designs" such as torn edges or leather borders, this is all about aesthetic. It's doesn't take a scientist to understand that people like things to look appealing. In the same manner a gamer loves his graphics to look as realistic as possible, so does any other user who sees imitation materials on their screen. Well designed abstract or purely digital layouts can look very nice, but they do not invoke most people's sense of value and worth. Furthering skeuomorphic techniques allows designers the license to introduce other larger changes (like new controls) with little more cushioning than some UI customization.