They are so protected that they never take risks so they are afraid to do so. A child never told to do chores becomes an adult who doesn't know how to do one. A parent that always hovered over the child on the playground instead of sending them out to play creates an adult reluctant to engage with any strangers other than online. So don't hover around the child playing in the back yard if they won't fall into the pool, let them make their bed and don't get upset it isn't perfect (it's made, that's progress, be happy with it). Note - constantly criticizing others for not meeting your perfect standards also gets partners/roommates to give up bothering doing chores, too.
A parent that never let the child make their own projects and do their own homework and constantly corrected and criticized teaches the child "you can't do this". Thus the young adult needs constant input and feedback or is reluctant to do anything.
And by not letting the child try and fail sports, arts and activities when they can learn to bounce back and go do something else fun, they don't know HOW to bounce back - end result, if they fail, they give up. If it doesn't come easily and immediately, they think they CANNOT do it and stop.