Abide, I'm not so sure. Here is my opinion of what allows me to be able to run injury free. And when I say injury free, I mean no injuries year after year. In my opinion, it is the same for most people though no one thing works for everyone.
1. Efficient running technique. Not perfect, but good. What this is is up to debate...
2. Good overall health: eating whole foods, hydrating, supplementing when needed. I could talk about this for quite a while.
3. Yoga: for physical, mental and spiritual health. Yoga is NOT stretching. It creates balance, aligns, strengthens and creates peace and relaxation.
4. I'm happy because I do what I love.
I don't do core exercises, work out or even run that much (I run 2-4 days a week). I'm a 'good' runner because I am efficient and healthy not because I am strong, run a lot and do speed work. I work EASIER, not harder.