Not so sure about your "pliability" theory and other fancy words, but I can give you a real life case study.
The #1 guy on our CC masters' team did not run a competitive step until his late 30s and is now an injury-free sub 15 min 5k and sub 4:00 1500 master. Other than a few nicks, aches and pains that come with training hard, he is good to go every week, every race.
Our #2 guy was a sub 9:00 3200 high schooler and sub 25 min college runner, has run and competed just about every year of his life and when healthy is a low 15 min 5K master. He is rarely healthy though and misses approx. 1/3 of our races. Amazingly, the guy can be out for a month and look completely unfit, but then throw on a singlet and blast a sub 16. A true freak of nature.
I (#3) took about 20 years off before tossing my hat back into masters racing and have had a decent amount of injury-free success. Still very durable and I have to think the 20 years away plays a big role.
Most of the other runners on the team struggle with injuries more often than not and just about all of them have never taken long stretches of time off. All of us who run competitively as masters recognize the value of "fresh legs" that have not been beaten down over the years. But alternatively, just about every runner worth his or her salt has run and raced their entire lives because they love it, are addicted and won't stop until they are face down in the dirt!