I took this class, and although I can’t speak for Prof Aspnes, I always imagined he just preferred writing the notes himself (since he can edit them) and might

I took this class, and although I can’t speak for Prof Aspnes, I always imagined he just preferred writing the notes himself (since he can edit them) and might want to publish them into an actual textbook some day. He wrote similarly thorough notes for his Randomized Algorithms class.