That's not true in the slightest.

The highest estimate for US emigrants is 9 million. Since there's no perfect way to track emigrants, the Dept of State uses available numbers from multiple sources and extrapolates it. The UN puts their estimate at about 3 million, but their data comes from censuses which can be inaccurate or non-existent.

Pew puts the number of college or postgraduate educated immigrants at about 13 million.

Even if we assume all of the emigrants are highly educated, we still have a net positive educated immigration.

There are a lot of good reasons to dislike the US, but we have always been pretty good about bringing in educated individuals.