I don't believe I said that online games invalidate the concept of wealth. What I was getting at is that online games hit the human motivational system in such a way that work and entertainment become the same thing, while simultaneously replacing physical goods with assets that are only real in the most gerrymandered sense of the word. This may not "invalidate the concept" but it sure causes people to act in ways that don't follow old-fashioned economic models.

Of course you can patch the models in light of this new data, but then they are new models, and you have surreptitiously modified the concept of wealth.

I would argue that the behavior of people who play online games certainly does contradict the folk conception of what wealth is and what it means and what it does.

(There's the side issue that I could point to literally any social/economic arrangement existing between human beings and an economist could explain to me why the concept of wealth still exists in that society. This is because the concept is sufficiently vague as to be inescapable. This does not necessarily mean that the concept has corresponding predictive power. Other concepts might be more appropriate. Other models might be more predictive.)