I'm not at all convinced of this. Considering that much the properties of the game that land such whales are based on triggering addictive behavior, it seems much more likely that the whales' income profile is similar to that of a lotto ticker purchaser in the US: relatively poor people.
But for a richer person, 3k a year is what they give to their kids for christmas in gifts.
That said, I don't think income level has anything to do with it. There are poorer people who shouldn't waste money to play the lottery or gamble in casinos, but do it anyway. There are also wealthier people who shouldn't waste money to play the markets, or other "casino/lottery for rich people" things, but do it anyway. It's just that our society is mostly oriented to treat the poorer people as compulsive gamblers -- which is treated as a moral failing -- and the wealthier people as "serial investors" or other terms which carry a more positive connotation.
https://www.theatlantic.com/business/archive/2013/11/your-br...
I once calculated what it took to have a fully upgraded base within a week (New Level 11--if I remember correctly ...) and it was something like over a million dollars.
And there were multiple fully upgraded bases within a week. Now that's a whale. o_O!
So I don't doubt your figures but there's probably a "one week whale" trajectory that's built into it to give quick gratification for something like $250,000. Still seems outrageous but they can discount digital goods differently than retailers can.
https://www.gamasutra.com/blogs/author/RaminShokrizade/91404...
One thing he mentioned is that what those whales do is "buy the server," literally buy the top spots in any competitive aspect through spending so much cash that the ante to get into it excludes everyone else. I think at that level everyone else really doesn't matter; it's a spending contest versus the other whales for status.
What happens is that eventually the ante gets so high that the other whales look for a new game or new server to fight over.
Although in reality, I bet the big spenders are not super wealthy. They probably spend way more than they can afford.
In a very real sense, the F2P business model only really works if the game is popular amount non-paying customers—otherwise, what would motivate whales to get into it in the first place? A whale-based system pretty much guarantees a product that's as widely accessible as possible.
Of course, it has its own massive ethical issues; I am no fan of the practice. (Not least because the people spending the most money aren't always the ones who can afford to spend that much!) But it does neatly invert the dynamic and uses the top 1% of spenders to finance something primarily enjoyed by the 99% who spend little to nothing.