Is there any scenario where a pro runner can gross $4M in lifetime running earnings?
Suppose you have more than enough money for you and your family to live out their lives without needing to worry about that. Now that's solved, you can move on to what you actually want to happen in your life, such as helping your kids become pro athletes.
from his wikipedia entry:
When asked whether the 4-minute mile was his proudest achievement, he said he felt prouder of his contribution to academic medicine through research into the responses of the nervous system.By putting in the same level of extreme effort into any classicaly well paying profession you would highly likely become very rich and successful.