“Inessential” is subjective. There isn’t a thing in the world where you can’t find someone making the argument that it’s inessential because it’s not essential to them.

And using price a test of luxury in a discussion about monopolies is kind of circular; it leads to saying that anything a monopoly has successfully captured is necessarily a luxury.

That gets you to prescription eyeglasses being a luxury, because I don’t need them, people can just buy contacts, and a monopoly has driven the price to astronomical levels.