>>3974693>Artists have millions of dollars they need to launderWhat a wild assumption, are all artists also secretly heavyweight drug pushers in your fantasy world?
A much more realistic scenario, if we're going for conspiracy theories, is that gursky bought it at such a high cost to inflate the prices of the rest of his work, both past and future.
But this still doesn't really hold water, as gurskys prints had steadily been appreciating for the previous decade before Rhine ii sold. 4 years earlier in 2007 a piece sold for ~$2.5m, and he has 12 of the 50 most expensive sold pieces to his name. Also, let's look at the heritage of the print, there's 6 in total, one each at MoMA, Tate modern, pinakothek and glenstone, gurskys own and this one for private ownership; the prestige behind this work is completely unmatched.
If you can't explain why this piece ISN'T worth $4m, which doesn't even come within 10% of the 100th highest auction price painting, then you might have an argument. But to the right buyer I would call this a relative bargain, if I was a billionaire I wouldn't flinch at buying a 3 metre long modern art masterpiece for my 6000 sq ft park row apartment for $4m, especially as it's not going to lose value.