It's a contrived example to show that when people say "I'm willing to pay for content", what they really mean is "I'm willing to pay a small amount for content that may or may not be as much as the content actually costs".
It's like saying "I am willing to pay for a car" and then complaining that nobody will sell you an Audi S6 for five thousand dollars.
This contrived example doesn't go anywhere near showing that. The fact that somebody won't single-handedly buy distribution rights to the movie doesn't mean they wouldn't pay a reasonable price for it ("reasonable" here meaning "in line with what other people pay").
If a no-name artist wanted $100,000 for their painting they'd be laughed out of most places and die well before ever selling a single painting. Your example works both ways.
Good/services are ultimately priced by the people willing to purchase. The producer can charge more than what people are asking - but can only go so high. The higher the producer charges, the less people buy their good/product. Sometimes this trade off is worth it (ie. luxury brands).
If nobody was willing to pay so much as a penny over $5,000 for an Audi S6 you can bet one of two things happening:
a) An Audi S6 would be sold for $5,000 (and never see production again)
b) No Audi S6 would ever be sold (and never see production again)
The example breaks down with torrenting because it introduces a third option. For the no-name artist,
a) Some people would pay $100,000 and get the painting.
b) Some people would think $100,000 is ridiculous, not pay, and not get the painting.
c) Some people would copy/steal/whatever the painting, and get the painting for $0.
Is it really surprising that many people choose c? Those people might say they'd actually pay for it if it was $10 instead, and some of them might be telling the truth, but I think many people would still choose option c. $0 is hard to pass up.
Some Audi S6 would be sold for $5,000 by desperate salespeople who need to get it off the lot. I just left it out because option A isn't all that realistic in either scenario.
Option "D" (offering to pay, taking for free) comes with knowing that the artist might not be able to support themselves to make more. I've always supported artists/studios I want to see create more art and I think any adult pirating understands the economy enough to know this - and most teenagers understand it on some level (but also understandbly aren't usually made of money).
One could also argue that increased exposure is a form of indirect profit. If 3,000,000 people steal a copy of the painting someone might be willing to buy that painting for $100,000 for bragging rights. Hey guys, I own the original painting! This exposure could increase their potential sales.
The issue of pirates is never black and white. Frankly, the music industry would never see $0.01 from me if I couldn't pirate/listen to free on YT and decide "I wish to support this artist and hopefully hear a new album from them in the future."
I know I'm not the only person who would never spend a single penny otherwise.
It's like saying "I am willing to pay for a car" and then complaining that nobody will sell you an Audi S6 for five thousand dollars.