This is not true. It’s a pernicious lie that the United States has always been doors open, and this falsity makes discussing this topic increasingly impossible because it’s like there’s two different realities that aren’t reconcilable. The US became the economic powerhouse and world power it did during the most restrictive period of its immigration history. The amount of immigration over the last 30 years, and especially over the last decade, is completely unusual and unprecedented. I can go to neighborhoods in the city I grew up in where I played baseball as a kid and it is quite literally completely foreign. A lot of people, and you seem to be one of them, think that America’s immigration system is a cosmic vacuum cleaner that scoops up would-be Einsteins from around the planet and plops them in US cities where they churn out unicorns between writing an opera and running a 10k. This isn’t the case.