I love that you say some anodyne things and then, with no actual facts or reasoning, conclude that the "true issue" is something that fixes blame and dodges the issues raised in the article. And, naturally, is a classic example of the fundamental attribution error at work.

As somebody who has gone over the past decade from no exercise to running 15+ races and is now training for my first triathlon I am happy to say that "will to exercise" is not actually the problem for anybody I know. That certainly wasn't my problem.

The good news is that people actually study this for a living. If you want a readable introduction to the limits and uses of willpower, McGonigal's The Willpower Instinct is a fine place to start understanding why, "Oh, those people are just weak," is a lazy and wrong answer.