What business practice did progressive attack and eventually defeat?

Progressives attacked and eventually defeated the practice of monopolies and trusts, which dominated many industries in the late 19th and early 20th centuries. They argued that these entities stifled competition, exploited workers, and harmed consumers. Through antitrust legislation, such as the Sherman Antitrust Act of 1890, and vigorous enforcement, Progressives aimed to dismantle these large conglomerates and promote fair competition in the marketplace. Their efforts led to significant reforms that reshaped the American economy and regulatory landscape.