Maybe van Gogh had to get up in the morning, paint some picture to live

Actually if memory serves, van Gogh never made a living off of his artwork (not that he didn't try, his artwork just didn't sell). He survived off of an allowance given to him by his brother.

An even more interesting case is Leonardo da Vinci who did make a living from his painting, but get this... it was largely to support his passion for science and engineering. Its hard to imagine supporting your engineering activites with artistic income. Today, the situation would be entirely reversed.

-Blake