My theory on this is that entrepreneurship has become more accessible in recent years. This means more Americans are starting companies thus reducing the proportion of startups founded by immigrants. Of course foreigners can do the same from anywhere in the world; a startup based in India can serve US-based customers just as easily.
Many tech startups from the 80s and 90s were started by founders with advanced engineering degrees, many of whom were foreign-born. But times have changed and now you can found a tech startup right after high school.
Tech startups are also not as risky as they used to be, and they've become more glamorous and fashionable in recent times. I've heard the number of American kids enrolling in CS programs has also grown in recent years.
Many tech startups from the 80s and 90s were started by founders with advanced engineering degrees, many of whom were foreign-born. But times have changed and now you can found a tech startup right after high school.
Tech startups are also not as risky as they used to be, and they've become more glamorous and fashionable in recent times. I've heard the number of American kids enrolling in CS programs has also grown in recent years.