The perfect system is a mythological ideal. It may or may not exist, but it is possible, even likely, given the LawOfTheEternal.
Consider this: AllDataRelatesToOtherData, the shell could be seen as one's interpreter environment where one accesses a giant DataEcosystem, made abstract with a UnifiedDataModel. I.e., file data, the network, all these system-level things drift away as one accesses a view into the data universe through conceptual labels linked and grouped together in complex tree-like way (FractalGraph) and navigable by peers of data stewards (formally librarians?). The windowing system goes away, as the desktop was a crude metaphore to begin with, and a ThreeDimensionalVisualizationModel shows you all data, while your LanguageIsAnOs allows you to build MashUp's of mini applications that link loosely coupled, modular, data objects (ObjectOrientedRefactored) together in more and more interesting ways.
Must follow the OneTruePath...