Wall Street Journal :: Like the massive declines in the nation’s steel, oil and automobile industries in decades past, the disintegration of the telecom business is leaving deep wounds in the U.S. work force. But labor historians say telecom stands out for the unprecedented speed of the boom-and-bust cycle. After telecom was deregulated in 1996, it quickly expanded by some 331,000 jobs before peaking in late 2000. Since the downturn started, though, companies have announced layoffs that have wiped out all those new jobs and more — a total of well over 500,000 workers, according to a tally by The Wall Street Journal. By contrast, it took two decades for the ranks of the United Auto Workers to fall to 732,000 from 1.5 million, as the auto industry was forced to become much more efficient in the face of foreign competition.