The general pattern is that big markets create big players, but also increase the amount of "effective" diversity and competition at the local level. The small

The general pattern is that big markets create big players, but also increase the amount of "effective" diversity and competition at the local level. The smaller automakers of the 1950s and 1960s were essentially monopolies in their own countries; whereas with the borders coming down, manufacturers are incented to both compete and diversify in a meaningful way, so that some fraction of them can hold on to their share of the bigger, unified market.