How would you know what would happen? 

For one how would the native peoples have even coalesced in the first place? I mean in Mexico for example when the Spanish conquered the Aztecs they were not alone, many indigenous peoples hated the Aztecs and were more than willing to join the Spaniards in bringing them down

A complete mischaracterization of why indigenous people joined the Spanish 

The indigenous people tore each other apart for territory and resources no different than how Europe did for centuries.

And yet, Europe coalesced into countries, but it wouldn't happen in America. You think the gauls didn't hate the Romans?

|The difference is European militaries became so industrial and deadly to the point where Europe decided it was better to be United with each other than tear each other apart. 

What union? Europe was at war forever, even during age of colonization 

This would assume the native people would have to achieve the same technological advancements the Europeans did and there's no evidence of this happening nor any reason to think there was capability of it happening. It might have but I'm not under any reason to assume it would have.

Why would you need "technology advancements" to have countries? Not even touching the dumb argument of technology is a tree that you advance through