Anyone who has ever had a body is probably familiar with the concept of the whole seeming OK, while there's something unhealthy happening in the small. I'm not rejecting other metrics, but I don't think this is irrelevant to the economy at large.
The comment you're replying to pointed out that the absence of a wage or presence of a low wage probably does not correlate with an equivalent amount of passive income for the vast majority.
You reject this and call it "vague speculation", for which I assume that the alternative theory is that there's a substantial majority of passive income earners at the bottom of society. It's an interesting theory.
It's possible. More economically savvy people = more early retirees. Higher rents could also be a factor (some people might be able to sustain their families with previously worthless property and low wages). Let's not call these people "bottom of society" though. I know a few with 0 wages and 7 figure capital incomes.
Because it isn’t. We have other indicators for that and GDP growth is one of them. Median wages are affected by so many factors that they invalidate such conclusions. Also, wages aren’t the only money available for spending, there‘s capital income too.