The extinction of any species is not sudden but it can be. Scientist have been warning about particular species becoming extinct or will be extinct in some future foreseen time line. The same goes for humanity or individual families within humanity. There are many levels of extinction.
The physical death of every individual is a form of individual extinction.
A family which falls a part into sin and lawlessness. Will become extinct in name and then by blood in just a few generations.
A nation which falls victim to apathy, oppression and authoritarianism will become extinct in a few decades or less. Probably less.
A worlds population can also become extinct when global insanity becomes additively rampant. This can take a thousand years which can culminate in sudden global suicide. Started by the controlling and elitist few who wrongly think they will be OK. Their bunkers will become their coffins.
To avert extinction at all levels. One should live by their own free choice without fear or threats. To love one another. To live in peace with everyone. To exist in harmony with all of creation. All of this must work together like a complete logical formula.
Musings of an American Truck Driver