By that definition, 3 out of 4 millenials are priveleged.
At that point, I'm not sure it's a useful term any more.
To give an extreme example, the majority of people in the US don't have to deal with what those who live on reservations have to deal with. That means that the majority of people in the US are privileged in a way that those on a res aren't.
I've always thought of the discussion about privilege to be a very American way of talking about human rights. We can't possibly talk about having enough food, housing, safe interactions with the law, etc. as rights, and thus those who don't have that are being denied their basic rights, so instead we talk about those things as privileges that are denied to a segment of population.
I would much prefer talk about these things as rights, personally.
The term isn't normally used in this relative sense, though. The oxford dictionary says that privilege is 'a special right, advantage, or immunity granted or available only to a particular person or group'. Something the majority enjoys is not a privilege.
Further, no part the definition you quoted restricts a privilege from being enjoyed by the majority.
For housing/food, sure - in the USian context it doesn't make sense to talk about such things as "rights" because they'd have to be provided by somebody else [0]. The existence of life's basic necessities is actually not guaranteed and it is worthwhile to remember that. (However this framework says nothing about the idea of distributing surpluses to people who couldn't otherwise afford it, just that it does not constitute a "right").
But inverting the sense and labeling their presence "privilege" is a completely regressive zero-sum framework, ultimately promulgated by political shills that are more concerned with bolstering their followers rather than actually fixing problems.
This is especially clear when talking about things that are rights, like say simply not being murdered (eg by the police). By labeling as "privileged" the people who are just not having their rights violated, the tone is set that they are the exception. The "privileged" group then checks out of the conversation (as they're being told that the problem does not directly concern them), while the ire of the "unprivileged" group is harmlessly directed at the "privileged" group instead of their actual oppressors.
[0] It's the distinction between saying whether a "right" to Internet access implies a free basic monthly service, or merely disallowing the possibility that one could be banned from the Internet via governmental action like an explicit law or "private" "three strikes" system.