29 years old here. I think maybe one reason the thought of "young producers" is present is because a lot of them frequent forums and other electronic feedback devices. In other words, young people utilize and are more "active" on social media and other Internet means that "older people" (since when did 30 become old? haha).
Also, societally, things are geared towards the younger generation. Music, advertisements, media, products, fashion...all are heaviliy skewed towards young people. Sad, really.