In this sense, calling a video game an RPG definitely does have meaning.
And
the reality is that no one person gets to decide what is and what isn't roleplaying, or a roleplaying game.
Are sorta funny together.
If you really believe the second, then the first is no more meaningful than the claim that it is not an rpg, and the word "definitely" is definitely wrong.
Conversely, if you believe the first to be true, there must be some way for a person to validate that calling something an rpg has, or does not have, meaning, in some definite sense. In which case, the second part is wrong.
(Me, I'd go with the second part being right, were I you. Especially because, if you don't grant that an avatar in a computer game is really more of a "character" in the tabletop rpg sense than a checker is in a game of checkers, your "measurable, mechanical character progression" also would apply to pieces in checkers.)
EDIT: I can easily see how one could approach play in a tabletop game as though it were constrained as is a video game. I have never, however, seen a video game that can handle play as occurs in my tabletop game. There is a difference, even if you choose not to partake in it.
RC