Agreed - the article makes a dubious claim. Many universities regularly accept high school students that haven't yet gotten a diploma as part of their early admission process. All that is required are standardized test scores, a transcript showing what has been learned, and evidence of excellence.

The claim that MIT is somehow a national treasure and unique here seems to miss the point. I know this because I was accepted early admission to MIT and graduated from there.

Extracurricular activities and evidence of capabilities have always carried significant weight in MIT's decision making process, but this is also the case for many other schools. It's only the graduate school process that requires evidence of completion of lower education. Try getting into a PhD program without a high school diploma or an undergraduate degree. And no, I'm not talking about honorary doctorates.