I've been programming since the early 90's, and back then pretty much all my coworkers were other US citizens. I started to notice a shift toward the mid 90's

I've been programming since the early 90's, and back then pretty much all my coworkers were other US citizens. I started to notice a shift toward the mid 90's and then, by the late 90's, they were practically all Indians on H1B visas. Nobody from Russia, China, El Salvador, Brazil, Japan, Botswana, Ethiopia or even Bangladesh or Pakistan - virtually every programmer I met was an Indian citizen in the US on an H1B visa. I saw this across ten employers in two different states. Every tech conference I went to, regardless of city, was full of Indian citizens with heavy accents, and me. There's a prevailing belief that US employers prefer H1B visa holders because they'll work cheaper and not complain about poor working conditions but if that's true... why computer programmers, specifically? Why are there _any_ Americans in the organization? Surely the product owners, project managers, scrum masters, HR staff, janitors, facilities maintenance, receptionists, directors, VPs and CEOs could be filled cheaper and less complainier by an H1B visa holder too? I have yet to find a plausible explanation why specifically computer programming (and no other career) is dominated specifically by Indian citizens (and no other nationality).