I guess my question is that is it likely a person would get the outsized health benefits because they commit to the minor health change which then causes them to commit to more later.
Being able to force myself to stick to something hard/painful causes me to also expand my ability to stick to other things.
And when I can't run (for example due to injury) it also affects my ability to stick to a lot of other things that should not be affected by my knee.
Another reason why I think running is so beneficial is because when you start it you see obvious, epic improvements in your performance.
I literally was doing runs I did not think possible just a month earlier.
It changes your perspective on what is and what is not possible.
And if this happens to you it may cause you to start investigating and making a lot of other health-related changes.
On a more micro level, a good run can make the rest of life's challenges much less daunting...as I say to my wife: busy days seem a lot less overwhelming if you start them by dragging yourself out of a warm bed to run 8 miles in freezing rain.