To break a habit, you have to replace it with a different habit. Willpower is one of the ways to do that, but others are more successful on more people.
The reason why so many people hire a coach for physical activities, diet or even life decisions isn't so much that these are extremely specialized domains that need high expertise; it's that having someone make the decision, i.e. not relying on willpower, is often more effective and easier. It also leads to accountability: you have to show results to someone else, not just to your brain. And for most people, that's also more effective and easier than willpower.
Telling people to get over themselves and take charge is generally a well-meaning, but often misleading call to action. And after a couple of failures, the lesson they'll learn is that they're weak and ineffective and there's nothing that can be done about it, which compounds the problem instead of solving it.
I think there is a fundamental misalignment here about what constitutes willpower.
The coach isn't a contradiction to willpower. You still make the choice to get up and go when you are lazy, you have just changed the incentives and accountability.
It also takes willpower and initiative to hire a coach.
If you avoid anything difficult and quit the second things get hard, no a mount of support will help.
By all means, use every trick in the book to make it easier. However, you are setting yourself up for failure in life if you avoid everything that requires effort, or think everything can be made easy with enough tricks
For some reason you and others seem to think every action or decision takes the same amount of effort and willpower. That's the only contradiction I see in these comments which is causing all these conflicting opinions.
The reason why so many people hire a coach for physical activities, diet or even life decisions isn't so much that these are extremely specialized domains that need high expertise; it's that having someone make the decision, i.e. not relying on willpower, is often more effective and easier. It also leads to accountability: you have to show results to someone else, not just to your brain. And for most people, that's also more effective and easier than willpower.
Telling people to get over themselves and take charge is generally a well-meaning, but often misleading call to action. And after a couple of failures, the lesson they'll learn is that they're weak and ineffective and there's nothing that can be done about it, which compounds the problem instead of solving it.