After a 15-month investigation, the House Judiciary Committee issued a 449-page report Tuesday that condemned some of the United States’ largest and most valuable technology companies as “the kinds of monopolies we last saw in the era of oil barons and railroad tycoons.” Amazon, Apple, Facebook and Google were no longer “scrappy” startups, the committee found, and House lawmakers recommended imposing restructuring regulation on them. The committee said that the companies had used their power to set prices and stifle competition in a wide swath of industries. “These firms have too much power, and that power must be reined in and subject to appropriate oversight and enforcement,” the legislators wrote.