The evolution of the surfboard was driven by performance.  From wood boards to lighter wood boards, like balsa wood, to foam core.  From heavier foam cores to lighter foam cores, lighter and thinner wood stringers etc.

Take two long boards shaped the same one built to weight 16lbs and the other built to weight 25lbs you'll will find the lighter of the  two to be more maneuverable.

Something that may be over looked in the evolution process aside from boards becoming lighter is the way fins evolved too.

In the early 60's virtually all surfboards had a "D" type fin. And the fin was placed right in the tail. We all found out over time that less fin area made for better performance and well as moving the smaller aspect fin up from tail made for better turning ability.

D.R. 

The above fin was  typical of early 60's designs.

The below fin was one of many more performance fin designs from the mid 60's and later.