Read this article of how tech corps here in the US prefer people from India to work here: http://www.latimes.com/business/la-fi-indians-in-tech-20150812-story.html
There are bunches of such articles. Given them….just how do you think US non-indian citizens are to compete?
Here’s another article of the same: https://townhall.com/columnists/michellemalkin/2017/03/08/a-day-without-american-tech-workers-n2295606
One other article that clearly explains the extent and history of H1B and its affect on US businesses and against US-born citizens: https://www.theverge.com/2017/4/20/15370248/trump-h-1b-visa-reform-tech-worker-outsourcing-cap
I hope you understand from these articles what US-born Americans face when attempting to get work in US tech companies.