And if you are extraordinarily lucky, perhaps you will get to keep it. More likely, some ordinary life obstacle will come along and wipe it out. When your car breaks down and you need to spend $1000 getting it running again so you can keep your job, are you going to leave that savings money alone, or are you going to spend it? Of course you are going to spend it, because the alternative would be going (further) into debt, and then you would have to spend the next 12 months paying off that debt instead of saving any more money. But in that 12 months, some other thing is bound to happen: perhaps you'll get sick, or you'll have to move and put down a new rental deposit, or any of the other million things that constantly knock people's lives off balance.
It takes multiple consecutive years of good luck before one can get to a position where your advice would be applicable.