"Soonish" at the time scales of current demographic trends is still hundreds, if not thousands, of years for even the most rapidly aging country. And cease to

"Soonish" at the time scales of current demographic trends is still hundreds, if not thousands, of years for even the most rapidly aging country. And cease to exist is a bit dramatic, certainly populations will decline given the current replacement rates in many westernized countries, but they aren't going to disappear. They will decline to some lower steady state, but nowhere near zero.