Conversation so far:
How come Cornelius Vanderbilt focused on steamboats?
A ferry entrepreneur named Thomas Gibbons asked Vanderbilt to captain his steamboat between New Jersey and New York. Although Vanderbilt kept his own businesses running, he became Gibbons's business manager.
How did Cornelius Vanderbilt make all his money?
He was an American business magnate who built his wealth in railroads and shipping.
did Cornelius Vanderbilt get along with Gibbon's son William?

Question: Why did he stop working with Gibbon's son?
Self-contained rewrite: Why did Cornelius Vanderbilt stop working with Gibbon's son?