I'll flip your question on its head: why are the people filling these roles so heavily skewed to one country?
1. Canadians have TN visas, so they prefer to use that since there is no lottery for that and it's a simple process of taking your offer letter and have CBP stamp a 3-year TN visa. Even though it is not dual intent, people can and do apply for green cards on TN status since for Canadians the wait times are current and they can get a green card before they need to renew their TN visa.
2. Australians have E-3, so that is what they will use.
3. The Chinese use H1B's but the numbers have dropped as more Chinese prefer to stay in China or return there after their foreign education since a lot of big Chinese tech companies have sprung up.
4. Europeans either do not want to move to the US, they sometimes don't try to have a prospective employer sponsor for H1b visas since a lot of them seem to believe that Indians have a monopoly on those visas.
You're left with mostly Indians, most of who study STEM subjects in college, overwhelmingly come to the US for studies and then hop on to work visas post-graduation. Most of the highest paying tech employers in India are American companies even then many Indians still want to move to the US since there are still a lot of socio-political and quality of life issues in India.
Take all these points and that's how so many H1B's go to Indians.
1. India is poor but not too poor
2. It has a huge population
3. A lot of upper class Indians already have family in the US
Of course, it is not clear why any of this should matter. Why should it be capped by country (as opposed to continent, zipcode or planet?)
It's supposed to be accepted as fact that if there are a lot of non-whites somewhere, it's simply because they're better. But if there are a lot of whites somewhere, it's because of racism.
Their numbers are so high simply because they represent almost a fifth of humanity - there are almost as many Indians as there are people in Europe, South & Central America put together.
Sure, it matters because there are tens of millions of black, hispanic, and latino US citizens -- numerous with CS/STEM degrees -- who cannot get into FAANGs. Many end up in retail or as best buy tech squad reps or tmobile store salespersons.
Yet we're told that someone from a foreign country is a better candidate for these FAANG jobs. In my experience, half the foreign workers cannot even speak english legibly.
Do Americans and the US Government owe at least some chance to local citizens who are being passed over for jobs generation after generation?
FAANGs aren't discriminating against black, hispanic and latino US citizens. If someone can't get into FAANG its not because of their "race" or "citizenship", it's because they can't pass the hiring bar -- whether hiring is broken is another question, but hiring isn't biased against blacks latinos and hispanics.
> Many end up in retail or as best buy tech squad reps or tmobile store salespersons.
This comparison is disingenuous. Had you said they therefore have to work in the government sector as software engineers, I'd say you might have a point. But your comment reads as: "because they can't get a job as at FAANG they work at t-mobile as salespeople.