A diamond has a certain weight, brilliance, color, and cut. If we put the diamond having all those qualities in a bucket of mud, do the carats, the brilliance, the cut, or the color change? All the qualities that are inherent to this gem remain the same.
Our Buddha Nature is like that diamond covered in mud. The Eightfold Noble Path has nothing to do with ‘producing’ Buddhahood. It is a path of separation from the two veils of wrong views and afflicted emotions, which hinder manifesting our own and perceiving the Buddha Nature of others.
If we did not have Buddha Nature, there would be nothing we could do to produce it. Something does not become what it is not. The only reason that we can manifest full, complete enlightenment is because we have Buddha Nature, not as a potential or seed, but just as the diamond in our example, with all its qualities fully and completely present.
If Buddhahood could be or had to be developed, it could also be lost. However, Buddha Nature is complete and perfect. Just as inside the bucket of mud, the mud never penetrates the diamond or mixes with it, our afflicted emotions and wrong views never alter in any way our Buddha Nature.