Admittedly I'm over a decade out of university so things might have changed, but when I was getting my masters in mathematics several of the math professors had various 'side hustles' doing cool and advanced stuff at startups and in industry or finance.

universities are dominated by anti-capitalist sentiment

I know this is trendy to say and I'm sure there are individual universities where it is true, but I see little evidence for it at large. If nothing else every hedge fund and investment bank in the world basically only hire university graduates, and they can hardly be accused of being anti-capitalist. Every economics course I ever took was based, almost axiomatically, on the premise that capitalism is awesome.

University graduates are not the same as professors.

The econ class I took at Caltech was taught by an award-winning leftist anti-capitalist professor, and if you didn't regurgitate his ideology on the tests, you got a bad grade.

Hedge funds only hire a particular subset of graduates. A lot of left-wingers set aside their ideology to get those high salaries.

My father was a finance professor at two colleges. He was the only faculty member who believed in free markets. He was constantly challenged in this by students and faculty. One time the faculty even challenged him to an open debate - the faculty against him. He took them apart. Faculty and students came up to him later saying they had no idea there was even a case for the free market, and thanked him for opening their eyes.

I wonder where you suppose Sanders' constituency comes from?