If Columbus had not discovered the New World in 1492, Pedro Álvares Cabral would have on April 22, 1500.
Discovery was inevitable.
And so was the destruction of the Indian population and culture. I cannot imagine a different outcome—a metal-using culture capable of trans-Atlantic voyages encountering stone-age cultures. In Mexico/Peru the disparity was less because of the Indian civilizations, (yet in spite of that advantage or perhaps because of it, they were conquered in short order) but in North America the uncivilized Indian really didn’t have a chance. Forget disease, economics doomed them. How many acres would it take to feed a European farming family vs Indian hunter-gatherers? The only places the Indians could hang on to were environments to hostile to be desirable to the European settlers.
Let us suppose the Europeans were the stone age people, and the Indians were the advanced (equivalent to 1492) people.
The Indians discover Europe, take captives and return home. Soon the diseases picked up there in Europe kill off most of the Indians in the New World.
It is STILL the White Man’s fault!