Despite the tone of the article, Kroc did not just swoop in and capitalize off of the Brothers' genius. If anything, they were an albatross around the company's neck, as their contract specified that Kroc basically wasn't allowed to change anything. Fortunately they got "creative" to get around these restrictions.
If you are interested how McDonald's became a company that is recognized around the globe, I would highly recommend the book Behind the Arches. A very interesting corporate study.
One of my favorite anecdotes: 80-year old Kroc's favorite pastimes was flying around in a prop plane with a highway map scouting out potential McD locations.