Good evening, beautiful people. It's another beautiful moment with you 
It amazes us that God in heaven even attests to the wickedness of man in the book of Jeremiah 32:33.
"...they have turned unto me the back, and not the face: though I taught them, rising up early and teaching them, yet they have not hearken to receive instruction."
God wondered how the people He created turned against Him, despite all the teachings in the Bible, despite all the commandments. People turned against God to do that which He opposed. Hence, if humans could do that to their creator from the beginning, it is likely going to continue. Yes, evil could abound in the world even more.
Also, many people serve the devil not God and the Bible says even their master has sinned from the beginning and he's looking for more so with him. Besides, evil gets much on earth because the devil, their adversary, was cast away from heaven and thrown among them on earth. Evil gets much on earth because the devil is not far away from them, he moves around roaring and planting evil in the heart of man. The devil makes men hate one another unnecessarily. Brothers killing each other, sisters betraying each other, fornication and adultery abound even in the house of God. Family members engaging in incest. Homosexuality became the order of the day, and many other atrocities that sadden God's heart abound, because many chose the devil instead of God. They traded Jesus for barraba. How won't evil abound?
They allow the devil to control and govern their hearts. Even when the Bible has clearly stated that anyone that sins is of the devil. Many people despise the gospel and do not retain God in their knowledge. Romans 1:28. So, they continue to do things that are not convenient and make evil abound. Until we all resist the devil and go back to the most high God, evil may abound more and more.