America didn't just get immigrants because it was the 'land of the free'. America got immigrants mainly because they were giving away massive chunks of land and because of the perception that America was filled with opportunity. The reality was of course much harsher and as it turns out the 'free' were never so free but people still continued to emigrate there in droves.
Put it this way. Tablet PCs have been around a long time but suddenly Apple comes along and markets a tablet PC as an IPAD. Even though tablet PCs are not really 'new' technology all of a sudden every kid on the block has to have an IPAD. Not because the IPAD is BETTER but because it was marketed better. Understand?