Is this really a modern trend, or just cherry picked data? This article needs a more thorough statistical analysis of car width through time.
I'm hesitant to take it at face value because, for example, to my knowledge the classic American land barges of the 60s and 70s (many of which are quite beautiful in an aggressive, almost obnoxious way) were quite wide - a 1969 Dodge charger is just a couple inches narrower than a 1990 Ford F150/Bronco, for example.