Just by taking a trip to the majority of American Spanish-speaking countries will easily show you how common Amerindians and Mestizos are. They make up the majority of the population. Now take a look at the English-speaking countries of the same area of the world. The natives are notable for their almost total absence.
The spaniards MIXED with the indians, creating mestizoes, many of them became rich and upper-class. How many mestizoes are in the USA compared to Latin-America ?? Ridiculous to say the british were better. The brittish didn't want to mix with them, they just killed them.
The two main reasons why former Spanish colonies have a greater percentage of people of Amerindian descent are :
1) The only two big and populous pre-Columbian empires in the Americas, the Aztec and Inca empires, became Spanish colonies. Their population densities contrast sharply with that of the nomadic tribes of North America. Nomadic hunter-gatherers just cannot sustain big populations. What happened in North America is similar to what happened in Europe during the Neolithic and Bronze Age; indigenous hunter-gatherers were overwhelmed and outnumbered by more technologically advanced farmers and stockbreeders. In addition, the US population grew extremely fast by any global standard thanks to a steady flow of immigrants from all over Europe.
From 1700 to 1860, the USA
doubled its population every 20 years ! In 160 years, the US population increased by 12000% !! (120-fold in barely 5 generations). How can you expect a constant population of hunter-gatherers not be swallowed in this mass ? If you think that today's difference of percentage between Amerindians and other US citizens is solely due to massacres, you are badly deluded.
There were plenty of wars between Europeans and Native Americans, and Europeans won most of them thanks to better technology. That's undeniable. The few settled native populations, like the Cherokees or Creeks, were relocated by force and countless people died in the operation. That's also a fact. Nevertheless, 3 million US citizens are still predominantly of Amerindian descent, and recent genetic studies revealed that a great number of White Americans (especially in the South-East) have some Native American ancestry. In Canada, as much as 4% of the population is Amerindian, despite heavy immigration from all over the world like in the USA.
2) In the first century of colonisation, the Spanish massacred or enslaved a lot of Amerindian men, while marrying, having sex with or raping the native women. It didn't happen everywhere, but the practice was widespread enough for the population of many Latin American countries to become mostly
mestizos. Genetic studies have shown that most men in Central America, Colombia and Venezuela today have European Y-chromosomes (but very often Native American mtDNA). In Colombia, for example, only 1% of the population is purely Amerindian. In Paraguay,
95% of the population is mestizo. About
80% of Mexicans are also mestizos, while approximately 10% are "fairly pure" White Europeans and 10% are Amerindians. If the Y-chromosomes and mtDNA were balanced between European and Amerindian types, we could assume that the two ethnic groups mixed peacefully with each others. However, the absolute dominance of Spanish paternal lineages and Amerindian maternal lineages leaves no doubt that the process was a violent one which eliminated male Amerindians from the equation.
Incidentally, I am not American, nor British, nor French, nor Dutch. I have no reason by my nationality to be more biased towards the Spanish or the French or the British or the Americans in this argument. My country didn't have any colonies in the Americas either. I am commenting it from a detached and neutral point of view.