When Oracle Corp. spent $28 billion two years ago to acquire electronic-records company Cerner Corp., it promised a revolution in health care technology. Co-founder and Chairman Larry Ellison declared the deal would help fix many of the labyrinthine industry’s ills by modernizing notoriously dated systems, and would create a major growth engine for his company’s earnings as well. Oracle “is now going to be at the center of the next generation of health care,” Ellison said in December 2022....