By 1706, Plymouth/Boston, New York City, Charleston SC, and several other British North American cities had been around for many decades. They were well established. They had thousands of residents, many native born. Second or third or even fourth generation native born British North Americans lived there by 1706.

One of the biggest reasons British North America was attractive to prospective colonists was its religious freedom, relatively speaking. French North America and Spain and Portugal's colonies had Catholicism as an official religion, so if you were Protestant and your religion mattered to you at all, British North America was the place to go.

Pre-1706 British North America had large populations of religious groups persecuted in Europe, including Puritans, Quakers, Huguenots, Jews, and others. There were plenty of others who just came for a better life, i.e. they were peasants who saw the prospect of earning enough money to buy their own farm, something you could do more cheaply in North America than you could back in Europe. But religion would have been one of your biggest motivating factors in deciding which colony to immigrate to.