I think that "white privilege" refers to two things:
a. A Caucasian does not even consider for one minute whether s/he will be served at a restaurant or allowed to buy a home in a particular neighborhood. In other words, for three centuries, the overwhelming number of people in this country have been Caucasian. So, of course, they never thought that they would be discriminated against. (Jewish people, of course, are the exception. They were often the victims of discrimination.)
b. Look at the Honorable Joseph Biden. He is a perfect example of "white privilege." Even his most ardent supporters will admit (in private) that he is a mediocrity. But because he is Caucasian, he has zoomed to the top, while more qualified -- and intelligent -- non-Caucasians never stood a chance to succeed in Delaware politics. Even today, the gentleman stands on the brink of becoming the President of the United States of America. (And, yes, it could be said there are some non-Caucasians who could have been a better Republican candidate in 2016.)
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Not to worry.
Within thirty years, according to demographers, Caucasians are scheduled to lose their majority ranking and just become one of several ethnicities. And by the end of this century, "white privilege" no doubt will be a forgotten term. In its place, there will be "Hispanic privilege" or "African American privilege."