Developed under the watch of Semon "Bunkie" Knudsen, the Mustang evolved "from speed and power" to the growing consumer demand for bigger and heavier "luxury" type designs. "The result were the styling misadventures of 1971-1973. The Mustang grew fat and lazy," "Ford was out of the go-fast business almost entirely by 1971." "This was the last major restyling of the first-generation Mustang." "The cars grew in every dimension except height, and they gained about 800 pounds (363 kg)." "The restyling also sought to create the illusion that the cars were even larger." The 1971 Mustang was nearly 3 inches (76 mm) wider than the 1970, its front and rear track was also widened by 3 inches (76 mm), and its size was most evident in the SportsRoof models with its nearly flat rear roofline and cramped interior with poor visibility for the driver. Performance decreased with sales continuing to decrease as consumers switched to the smaller Pintos and Mavericks. A displeased Iacocca summed up later: "The Mustang market never left us, we left it."