In Canada, the F-Series has been the best-selling line of trucks for 50 years, from 1966 through 2016.
Ford reclaimed the U.S. sales title in 1977 — and hasn't given it up since. That year, a copywriter for a Ford trucks magazine is said to have coined the phrase "Built Ford Tough."
"The success of our truck line has been that we've constantly tried to see what the customer wants in that vehicle and then keep raising the bar," Kreipke said. "To sustain sales, you have to constantly upgrade your product."
Not every change went over well with customers. Rounded "jelly-bean" styling introduced in the 1997 model year was abandoned during the next redesign after sales began to slide.
In 1998, Ford introduced the Super Duty name for the F-250 through the F-750, which mainly were used for commercial businesses. In the following years, it added more expensive trim levels with fancier interiors and more technology. In 2011, Ford pickups first came with an EcoBoost V-6 engine that increased fuel efficiency without sacrificing power.
The most important recent update happened in 2014, when Ford gutted its massive F-150 plants in Dearborn, Mich., and Kansas City, Mo., to retool them for building pickups with a body made of aluminum instead of steel to slash weight. It was a costly and risky decision, and though rivals such as General Motors have attempted to portray the aluminum body as weak, the changeover happened relatively smoothly, and sales continued to rise.
More recently, the automaker has added a 10-speed transmission and a host of driver-assist features. It has a diesel version of the F-150 on the way soon. Ford is reintroducing the Ranger midsize pickup to the U.S. in 2019 and, at the end of the decade, it will add a hybrid variant of the F-150.
"They're certainly positioning themselves to maintain a pure tech advantage over their competitors, and they also have a strong brand loyalty," Brauer said. "They have everything in place to maintain their dominance, but they do have to do what they've been doing, which is aggressive innovation. It'd be easier than ever for a competitor with a superior product to sway buyers away from Ford."