I read the article and think that he/she makes a good point. The point this person is trying to hit is: does this imply that more people do not like the style of older bicycles or that people are making lifestyle changes to ride bikes instead of driving cars or that the economy is not the greatest and people are getting bikes because of it? The article compares 2 markets (bikes and cars) where it doesn't fully reflect the market (only shows new cars/bikes). The full market is probably quite a bit harder to get data for (and that's probably why they don't show it) but it would really give a much better indication of what is happening.
I almost feel like this article is misleading because bicycle production is much higher than automotive production. See the following link under "Bicycle vs. car production"