They land on the shores of the Americas--the Spanish and French and Dutch and English. Depending on where they disembark they may find huge cities that rival those left behind, run by central governments with intricate legal systems. Or they may find peoples who live within their environment instead of trying to conquer it, not because they are incapable of doing so, but because they have found this to be the best way to continue and thrive. An intricate trade system exists among these people, running from north to south and east to west, with some nations serving the purpose of middle-men. They all have a system of education that does not involve congregating in separate buildings called schools, but none-the-less imparts the lessons that youth must learn to survive and live within the mores of their societies. While there are some inter-nation rivalries, stealing or murder within a band results in death or banishment and the occurence is extremely rare.
Recognizing how well these people have adapted to what is for the Europeans an alien environment, rather than make war on them or try to convert them to their religion and lifestyle, the Europeans interact with these peoples as equals. Over time, each culture, by its own volition, takes on what they find to be the beneficial aspects of the other while disgarding those traditions that no longer serve a pupose. Enjoying mutual respect they have no prohibition against intermarriage.
The scenario would not be assimilation into a dominant culture as was the goal of the 19th century but, instead, a blending.
This was not altogether impossible. The French voyageurs came pretty close to that type of society. But while this blending may have eventually led to some uber-race, separate Aboriginal cultures would cease to exist. Oddly enough, European extermination policies and then herding onto reservations may well have been what kept Aboriginal cultures alive in the long run. A total blending would have exterminated the cultures if not the individuals.
So is that better or worse? There's a thought to ponder.