There is less motivation if there is less hardships.

Most cases of top athletes come from a place of being doubted, put down by their surroundings, and more importantly, going through hardships.

It could be their parents are going through things
Or they were broke
Or they were homeless
They were cheated on
They were bullied.

Whatever the case might be, they had things in their life that would bring down any average person to their knees.

This is because an average person doesn't let their pain motivate them. These successful people did.