“Why not a spring powered car? I had toy cars which ran great by winding the spring”
________
“You may be onto something! Think of all the jobs for spring winders; all the health benefits of winding it yourself.”
Fat chance. It’ll be like the industrial springs in you garage...you’ll have to hire someone to do it for you, because winding the springs incorrectly could “KILL you”. Then they’ll charge you a $100 service call to do it.
We’d have to refine the mechanics with gearing and pulleys to maximize distance and minimize rewind effort. We have many household appliances where the dangerous elements are inaccessible, or difficult to reach by the foolhardy.