There is enormous division of labor and specialization in the historical socialist states. It is pretty much the same level of divsion of labor as the capitalist state it takes over from. Miners only mine. They don't make steel , by and large.
Doctors only don' t usually do much more than the speciality of medicine.
Physics profs teach physics mainly. Autoworkers make one part of the car . Maybe I am just being dense. Socialism has socialist or social ownership of the basic means of production. Capitalism has social production and private appropriation.