The same way real engineers work: classroom training in formal engineering, followed by years of experience under an accredited engineer in the field. There

The same way real engineers work: classroom training in formal engineering, followed by years of experience under an accredited engineer in the field. There is testing at each transition to weed out the skaters. Software engineers don't need to be computer scientists, in the same way civil engineers don't need to be materials scientists. There is a bootstrap process, and even in other industries not all engineers are PEs... but all projects are reviewed and stamped by PEs.