I get what you say, Steel's term of "labor aristocracy" is separated from those facts, as he uses them in a reduced Leninist sense, so that there doesn't have to be specific benefit as being part of the core is enough.

In terms of materialist analysis your point is in my opinion strong as it holds up that it can't be enough for us to have a term from one interpretation of theoretical framework that categorial contains the group we talk about, but doesn't allow us to differentiate farhter (if at all that is your goal).