Once Spain knew that their was gold in the New World, they could not stop their people from going to the New World. The settlements were to establish ports for the transportation of goods back to Spain.

As for the North America (excluding Mexico). The Europeans were looking into creating the same type of Empire that Spain had. The lure of Gold, and other wealth attracted the European monarchs to send explorers out. Once they set up settlements, the settlers looked for gold, and worried little about anything else. Although explorers still looked for the infamous NW passage- the main goal was to find wealth.