The "tough/hardass" coaching model occasionally works on the HS/college level because athletes have no control.

It largely fails on the pro level because athletes have more autonomy & understand their value

Pro's want to be treated as people, not subordinates.

Why? A thread:

It's not that young athletes don't want the same things (autonomy) as older. It's that there's an inherent power differential and they are nearly powerless to escape it.

They "survive" the 'tough' training, they don't thrive under it.

Human motivation is very simple. Self Determination Theory boils it down to 3 basic needs:
1. Feel like you belong
2. Feel like you can make progress
3. Feel like you have some control over your life (autonomy)

Intrinsic motivation largely fuels the "obsession" you see from top performers to practice their craft over and over.

That doesn't come from a coach or someone dictating and directing. Over the long haul, it has to come from within.

As you can see, the "hardass" all the time approach runs counter to at least one of our basic motivational needs.

Over time, you erode self-motivation and have to replace it with something else, or else you lose people.

That something else if often more extrinsic motivation.