Design language, like any language is metaphorical. The thing that makes these skeumorphic designs work so well is that it kinda forces a consistent metaphor, and consistency above all else is huge for UX. The fact that it's based on things we've seen in real life is also helps, as it means we can reason about the UI with the same faculties we've spent our entire life training.
Why are designers not understanding this these days? I think one reason is that flat UI is super easy. Skeuomorphic is extremely hard to get right, and if you don't get it right it looks super tacky. Most people who have the word "designer" in their job title don't have the artistic skills needed to pull it off. This is why most designers are opposed to skeuomorphic. Somewhere in between is the right approach. The Ne…
Even Apple’s initial move to a flat UI in iOS 7 suffered from this. It took a long time to get refined to the point of not feeling like a major step backward. I still preferred the look of iOS 6 to anything that came afterwards. The skeuomorphic designs were warm, inviting, and fun. They served as a nice juxtaposition to the rather austere hardware.