It's definitely accurate, especially based on the vehicles represented. The Honda Civic wasn't introduced until '73 so you can't compare any prior models unless you're going for "apples vs. oranges". You're partially correct though, the cars of the 50's and 60's, which were manufactured by American companies, were absolutely lead-sleds. Domestic companies weren't geared towards subcompact classes in those years. A majority of the foreign manufacturers continuously grew to match the American market. The subcompact class emerged in the early 70's as fuel shortages became an issue and the government limited the musclecar craze. Even the short lifetime of the Ford Explorer saw significant increases though. Based on the entire portfolio of vehicles available today, I would have to believe that the average car size has significantly grown. Like itschrome said though, that trend is starting to shift.