I disagree with your percentage breakdown.
Brennan made $106,443 from his products, for 45% of his income. He could have dropped the consulting altogether and still would have made a nice six figure salary.
Nathan earned 76% of his income from his products.
Amy earned 100% of her income from products (as best I can tell).
Products are not the same as software. An ebook is no less a product than a paper book you buy in a store.