Because obviously the intention was to compare Europe to Continental/Colonial America, rather than to emphasize the Europe of the 16th century as compared to the Europe of a later date!
By the way, there was no Continental/Colonial America in the 16th Century. Virginia Colony was founded in 1607. Unless you want to count the various failed colonies started by Spain, France, Russia, and others. Or maybe you think the author was referring to the medicinal skills of First Nations/Native Americans?