I'm curious what makes you think that. That is, of course, one of the general solutions put forth to the fermi paradox. Ie either the species develops species killing weapons (like nukes) or individuals gain massively destructive weapons. But I find these things unlikely. Even exploding all of our existing nukes in the most devastating locations would not destroy humanity or the earth. We'd bounce back - tho if such an event is inevitable, perhaps we would ride an endless wax and wane between devastating destruction events every 1000 years.