Global life expectancy has always been dominated by infant mortality. Stating this for anyone that is young or does not know. Humans did not somehow die at 30yo like the number appears at surface value. Most people died as infants or as young kids due to all the potential illnesses and complications in early life. People still lived to be 60-80 years old if they survived childhood.
If people do not stop having babies, the wars that are coming will cull the population. This is already the obvious tech bros plan for the future. This is why the super rich have their bunker islands already setup and secured.