Pickup trucks that cost $50,000 or more were a rarity on dealer lots a decade ago. But Detroit’s auto makers, eager for new sources of income, have been steadily yanking up truck prices—and finding that buyers will pay up for better engines and more frills.

Ford Motor Co., General Motors Co. and Fiat Chrysler Automobiles NV have in recent years introduced trucks at price points well into luxury-vehicle territory, offering plusher interiors, more powerful engines and premium options like massage seats and touch screens the...