1970’s Airline breakups were very beneficial to customers with lower prices and more routes popping up virtually overnight (though read “Hard Landing” if you want a more nuanced take), 1980’s AT&T breakup was somewhat beneficial in that long distance and cell rates went down but local rates went up (see “The Deal of the Century”), 1990’s California Energy breakups were basically a net negative for customers allowing energy market speculation and manipulation (“Smartest Guys in the Room”), and in a handful of examples like the Soviet Union or South Africa, deregulation lead to outright collapse of essential sectors in banking, agriculture, and energy and set society/customers back decades (“Sale of the Century”/“After the Party”).