Complex sentence: Many new industries were set up and run profitably during the wars and about half of them failed after hostilities ceased and normal imports resumed; but industry in the U.S. was advancing up the skill set, innovation and organization curve.
Split into simpler sentences: Many new industries were set up and run profitably during the wars and about half of them failed after hostilities ceased and normal imports resumed. Industry in the U.S. was advancing up the skill set, innovation knowledge and organization curve.