"The only thing that's changed is the competitiveness of the series. It's only become harder to win in our series as the years have gone by. Competition breeds good things, and that's what's happened here"

Al Unser's quote talks to the increasing competitiveness of the series he is referring to. He thinks that the competition has only end up being more extreme as the years have gone by, which this is an advantage. He believes that competitors types good ideas, and that this is what has actually happened in the series. This is likely due to the truth that as the competition increases, so does the level of ability and skill of the participants. As an outcome, the series has ended up being more challenging and satisfying for those who are able to be successful. This is helpful for the series as it motivates more people to participate and keeps the competition fresh and interesting. Ultimately, Al Unser's quote speaks to the significance of competition and how it can result in favorable results.