That is all what you need, if you take the time to at least look at the best known works of the different geniuses through the ages you will see they do not thousands of pages to describe a principle of nature and then find practical applications for it.

And this is true in many disciplines, for example some of the most beautiful music around the world is just a few pages long and yet that is more than enough for those masters to show their skills, so I am not surprised this is the case for Satoshi as well.