I can't say that anyone I know has ever actually believed this. The closest I've ever heard is "money is the only motivation for mercenaries," which isn't really the same thing.
I've also predominantly met people in my life who don't ascribe to this rule necessarily... but, that doesn't change the premise that the system we live in operates on it.
Considering we live in a country where growth in wages hasn't kept up with the rate of inflation in nearly 20 years, that appears NOT to be the case. There's a whole class of industry consultants called "efficiency experts" whose primary job is to figure out how to make workers do the same jobs for less money, or do more work for the same amount of money.
Your evaluation of our "system" is simplistic.
As an aside, Fredrick Taylor, the father of time-and-motion studies and scientific management
, had some really interesting tricks to motivate workers. In one, he'd just be chatting with the workers about him being an "expert" and start reeling them in with things like, "Well, a 25 cent a day man can do a little, but anyone can do that much. You guys can move a pretty decent load, like a fifty cent-a-day man. But a dollar-a-day man, now a dollar-a-day man could move that big barrel over there. Are any of you a dollar-a-day man? From the looks of you, I'd guess not." Sure enough, one or two would rise to the challenge of pride, honor, and social advancement. John Henry even challenged a steam-hammer.
One trick Bill Gates used at Microsoft was a special slide into the cafeteria that could only be used by programmers who'd accomplished some nearly impossible level of clever and complicated coding. People would work like dogs to earn the right to slide into the lunch line. Management genius.
What worries me is what will happen to labor when management finally understands how WoW and other online games can keep people intensely focused on irrelevant tasks for days on end.
"Carl, you look like hell!"
"I've put in 36 straight hours packing printers into boxes."
"At 850 boxes I hit level 37 and get the +3 Shield of Power."
"Jebus. You must be making a fortune in overtime."
"No, they don't pay me anything."
"Then why the f**k do you do it?"
"Because I NEED the +3 Shield of Power to smite Shelly in marketing!"
People will work like dogs for imaginary gold and pretend magical powers, en masse, and think they're recreating.
thinks the revelation that money isn't "real", a thing with physical position and mass, means it can't have real value. He's missing some abstraction layers or some little mental leap.
I could perhaps try to convince him either that numbers don't really exist because they don't have mass, position, or energy, or perhaps try to prove that the number seven doesn't exist in nature, even under a microscope.
"See, there are seven amoeba!"
"No, that's just four amoeba there and three over there."
"Now it's six amoeba and one amoeba. Still no seven.