It seems to me that determination often beats talent because people who are brilliantly talented think that "they have time", "it will be easy for them" and "they are already good"; thus never really putting great effort into anything.
On the other side, people with average talent and skill know that they need to try hard in order to do good, so they try hard. Unless, of course, they are among those that don't even attempt to pursue their dreams because they "can't become world class", as you pointed out.
I have met quite a few brilliant people and they do have that tendency to (falsely) believe that just because coming up with brilliant ideas is easy, then executing those ideas will also be easy. Which very rarely holds true.
I think part of the reason I have also done OK is because I am quite content "being OK" or "being quite good" and forget about the whole world class thing.