I have a friend who is working on breaking a motorcycle land-speed-record (http://bonnevilleproject.wordpress.com/) who was the first person to explain this to me. It's easy to dismiss drag racing as "build a big engine and step on it" but as he demonstrated (through examples like you have provided) any one thing can be broken down into millions of variables, and to compete you have to be willing and able to tweak at this level to rise above the obvious improvements (which quickly become commodity).