Seems like a wealth transfer from "developed country" workers to "less-developed country" workers and capital owners. The exact dynamics are of course hidden from that chart. The labels on the axes say that the peaks are gaining relative to the valleys in that chart.

A wealth transfer would cause at least one group to take losses, no? This graph shows growth for everyone.

No. There could be two phenomena occurring simultaneously: growth for everyone and layered on top of that a wealth transfer. The key term you're ignoring in my comment was relative: "peaks are gaining relative to the valleys".

I know you're into finance. Are you familiar with the concept of a long-short hedge fund? If so, you should be comfortable with the idea of focusing on relative movement of two assets within an asset class, hedging against the absolute movement of the asset class as a whole.

If you want to declare a delta between some hypothetical distribution and the actual distribution "wealth transfer", have at it. That is certainly irrefutable, albeit mathematically vacuous.

Not sure what you're getting at with "delta between some hypothetical... and the actual" but yes, I was describing something irrefutable. You'd asked what the chart meant. I looked at the axes labels and described the shape of the curve.

Middle class tends to rise off of the redistribution of rich class's wealth. Like I said, the second part of my original comment. (which is a good thing, so maybe "worse" is not the best word).