People write stories like this to demonstrate the importance of time when it comes to saving and investing. Maybe a 20 year old can’t save $250 a month (although I have known some that do, they are not as rare as you suggest).
But even if that 20 year old saves $25 per month they will be better off.
Yes some people can easily save $1k per month at 40. But odds are if you have not created a habit of saving and investing prior to age 40, you are not going to suddenly start investing that much money all at once.