This is wholly untrue. It is very possible to maintain a subset of the population to guard the knowledge of the fundamentals so that the rest never has to worry

This is wholly untrue. It is very possible to maintain a subset of the population to guard the knowledge of the fundamentals so that the rest never has to worry about the abstraction failing in any real sense. For example, humanity has abstracted away the vagaries of internal combustion engines for car propulsion through a standardized interface and the "last of the original abstractor's guard" for combustion engines died several decades ago.