Yes, I believe you can teach yourself JKD as long as you have the determination and perseverance. I was an athlete all my life with very little Martial Arts training compared to Bruce Lee. I read his books, opened my mind, and began studying Wing Chun, and Jeet Kune Do. I did this with his books. I later learned from pictures Bruce Lee was doing the same basic exercises I was practicing.
Although, I have great desire to train JKD with Sifu Inosanto I do not know when that may happen. He is in California, and I am in Washington D.C. However, I continue to train TKD, and during sparring I begin to understand everything Bruce Lee wrote at a feeling and experiencing level and achieving above the reading comprehension level.
Yes, reading books does improve a person's martial arts ability. That is how Shaolin Monks did it according to legend.