Before the Apple Watch was released, Samsung released 5 smartwatches, 4 of them were in 2014 alone. All 5 of those watches did not have any dedicated rotating/scrolling controls.
Once Apple Watch was released, Samsung stopped releasing new watches for almost a full year and then released the Samsung Gear S2. They took the form factor of the Moto 360 which everyone loved, and combined it with dedicated scrolling controls (something that Apple correctly solved with users using super small touch screens with their fingers).
This folding screen tech is a classic case of Samsung throwing spaghetti against the wall to see what sticks. Samsung starts with what new technology they can come up with, and try to cram it into new products. Apple starts with the UX, figures out what the problem is, and solves it using new technology.
I'm not saying Apple will never use folding screens, but so far, Samsung hasn't really solved any major UX issues with folding screens in that demo.
Every company reinvents and redesigns the exterior and UX/UI of its products to better user experience, borrowing from competitors is not some new concept, however the norm. This is not a Samsung versus Apple situation, this happens in the TV sector as well, company A puts a camera on their TV, company B follows, company C puts a mic in their remote, company A follows. This steers the user experience in a given direction. 3D for example was not well accepted, companies dropped support for it.
A crown dial for manipulating information is nothing new, classic analog watches use it to move the hands, Apple taken that concept and applied it to a digital UX/UI.