Micron Technology Inc. executives warned about a semiconductor downturn in late June, but now say that a “sharp and sudden” drop in demand exceeded even those expectations, suggesting the current chip glut could get a lot worse. Micron MU, 0.74% reported a worse-than-expected fiscal fourth quarter Thursday, with revenue plunging 23% from last year, but that wasn’t the big miss. Executives guided for $4 billion to $4.5 billion in revenue in the current quarter, more than $1 billion lower than analysts’ expectations, and suggested they could post a loss in the quarter even on an adjusted basis. “As we look...