What did Arthur miller mean when he said the Jamestown people were "individualists"?

In the Overture to The Crucible, Arthur Miller provides some historical context to help us gain a better understanding of what to most of us is an alien culture: the culture of the Puritans. Whatever Miller may think of the Puritans, he does at least acknowledge their strength in the face of extreme adversity. Despite the numerous hardships and privations they endured when they first came to America, the Puritans were able to survive because they established a communal society in which people supported and looked out for one another. However things may have turned out during the Salem witch-trials, the Puritans were inspired by their religious beliefs to work together to build a godly society on earth.
Contrast this with the original Jamestown settlers, says Miller. They were rugged individualists who came to America for one reason and one reason only—to get filthy rich. They had no intention of realizing any noble aims; they simply saw Virginia as a place to be exploited for personal gain and nothing else. As it was a case of every man for himself, the Jamestown settlement lacked any kind of common resolve or social solidarity, and the headlong quest for riches undermined what little stability existed. The end result, according to Miller, was that the harsh environment of Virginia effectively destroyed the Jamestown settlers.