Detroit’s Big Three automakers are showing a new sense of bottom-line discipline as they angle for any advantage in the race with Silicon Valley, and one another, to develop the cars of the future. This week, the companies — General Motors, Ford Motor and Fiat Chrysler — reported earnings that highlighted the underlying strengths in their basic business of building mass-market vehicles, particularly hot-selling trucks and sport-utility vehicles. Ford was the latest to weigh in, announcing Thursday that robust sales of its bellwether F-series pickup had fueled a $1.6 billion profit for the third quarter, a 63 percent increase […]