I recently heard a prediction that someone living today will live to 150 years old. When it becomes the norm for people to live well past 120 years, will this phrase go out of use?
I guess it’s like l’havdil when someone gets a sentence of “1000 years” in prison….just means definitely being in there for a looooong time. So when we wish “til 120” we mean you should be around iy”h for a loooong time! Just guessing here.