It seems like you are conflating a couple of ideas.

• Europeans did not need to “conquer” and decimate native Americans or enslave people in order for the descendants of these populations to have access to the “high quality” aspects of life. They could have simply traded with them for instance once the age of exploration came forth
• There are other nations on earth apart from those in Europe. Native populations could have eventually formed trade links with these other countries
• There is no reason these populations could not invent many of these advances themselves (especially with the assistance of trade) in due course (eg shipbuilding, steel industries, modern farming techniques, etc); as had happened in so many other countries in the world (e.g Japan modernised largely in a single generation, as did Russia)
• Many of the 2nd and 3rd world countries (as you describe them) are largely impoverished and brought low because they were under the yoke of colonial powers. They had great economic growth prior to this, and have grown well since independence. Had colonialism not occurred, these countries would likely have done much better
• Colonisation and slavery effectively created inter generational debt. Just like the son of a baker is less likely to attend Harvard than the son of two Harvard graduates – members of historically disadvantaged groups of societies such as Native Americans and blacks have quite the challenge to break out of their socio-economic conundrum, and societal prejudice against them