As someone who isn't a native English speaker, I've long noticed that, as you mention, "minority" doesn't mean "the opposite of majority" (I'm not sure since when, or exactly what it does mean; you say success is key, but success in what field - chess, boxing, beer-making? Listing just a dozen fields is probably enough to demonstrate that no minorities exist according to the "success" definition.)
However, to return to grandparent's comment - I, similarly to its author, have never noticed that the word "color" had been similarly redefined. Isn't "a person of color" the opposite of "white", where "white" means a having skin with a color at a mostly-agreed-upon pinkish/palish range?
Success means general economic success and low crime rate. "Minority" outside the context of politics means what you describe above - let's call this "minority_1". "Minority" as used by progressives (lets call it "minority_2") seems to mean a group of people that share uncommon visible characteristics who are also less successful (in the sense defined above) on average than the majority. Racism certainly exists - though progressives use a non-standard definition of racism, such that any member of a minority_2 can not be racist against a successful minority_1 or the majority. In fact, even discrimination against a successful minority_1 by the majority is seen as unworthy of note - an example of this is how no one seems to care about the obviously racist (by any common sense definition) discrimination against Asian students by Ivy-League universities. Asians need much higher SAT scores than white or black students to get a place in same.
"Person of color" is essentially a tortured, PC, language construction intended to enable people to avoid saying "non-white" (which, while descriptive, is apparently insensitive or something like that).
So, for example, mixed-race President Obama is a person of color, his African father is a person of color, and his White mother is not a person of color.
It's fairly situational and the lines are relatively blurry - for example, if I have one Japanese grandparent, am I a person of color or a White person?
However, to return to grandparent's comment - I, similarly to its author, have never noticed that the word "color" had been similarly redefined. Isn't "a person of color" the opposite of "white", where "white" means a having skin with a color at a mostly-agreed-upon pinkish/palish range?