A few observations, which may not be as informed as they should be, but nevertheless I think reflect intuitions of many:
1. I detect a life of frustration in his never being able to replicate the magic of his high school years. The comment from his first wife in 1974 that he was unduly devoted to running speaks volumes. Running by necessity requires a good dose of self-centeredness, but keeping the self-centeredness is balance and having expressions outside of running which are just as fulfilling seem essential.
2. Substance abuse addiction may well be the result of a poor genetic luck of the draw. I was not a Danielson caliber runner in high school, but did manage a 4:08 mile. I could only attend school on a track scholarship, and the one thing that helped me "make it" to a world of success beyond track was that I, through frankly dumb luck, just had no interest in alcohol or drugs (and was too shy around women to date anyone who would lead me astray). I have empathy for those stuck in this trap, but at the same time, we all need humility to understand that the addiction trap can snare us all.
3. I did not run 20 x 220 in 24 sec in high school. But I did do a lot of speed work - in retrospect - way too much.
It is possible to get high school runners to run fast times with intense speedwork, however, it is often the case that it does not help in long term, incremental development. (My high school coach ran for Igloi and it was remarkable what 30 days of that speedwork could do in a high school athlete). From looking at the tape of Danielson posted here, I can see why he so readily took to speedwork and likely became obsessed by it. He was a very, very strong high school runner who took to heavy speedwork easily, and like most of us, we become drawn to what we are good at.
4. The Times reporting so often centers on a narrative rather than hard facts and a coherent theme. This article about Danielson, however, is excellent, and reflects the Times at its best. I think most everyone reading it walks away with a sense of tragedy, and if thoughtful, we all should feel a greater sense of tragedy for the victim than for Danielson. But it is an awful situation all around.