Can a rich man enter the gates of heaven?
Big YES. It's clearly proven in Biblical history. Most people that are chosen by God to lead his children were rich or abundant in resources. Abraham, Jacob, and Job? They had such vast land and large number of animals they owned. Moses, King David, and many more. But there's a transition happening during the time of Christ.
As long a the rich man follow the rules of God, he can enter the kingdom of heaven.
But during our time right now, it's really hard for a rich man to enter the gates of heaven. Most of the rich men are preoccupied with the material things here in Earth. In their minds, they might think that they don't need God anymore because they already have rich resources they need.
Not only for the rich man, but also for the smartest people in the world. If I'm not mistaken, I think most of them believe that God didn't create the universe and God doesn't exist.
I wonder if there's any survey about how many richest and smartest people in the world believe in God.