A man lives 70-80 years trying to deny God's existence and invitation to eternal life leaving himself in hopelessness. Why?

"I, even I, have said in my heart with regard to the sons of mankind that the [true] God is going to select them, that they may see that they themselves are beasts. 19 For there is an eventuality as respects the sons of mankind and an eventuality as respects the beast, and they have the same eventuality. As the one dies, so the other dies; and they all have but one spirit, so that there is no superiority of the man over the beast, for everything is vanity. 20 All are going to one place. They have all come to be from the dust, and they are all returning to the dust. 21 Who is there knowing the spirit of the sons of mankind, whether it is ascending upward; and the spirit of the beast, whether it is descending downward to the earth? 22 And I have seen that there is nothing better than that the man should rejoice in his works, for that is his portion; because who will bring him in to look on what is going to be after him?"