Oh. Well then that totally negates the concept.
It sort of makes the story less compelling.
I could tell a similar story that actually happened over and over to me.
I would be in groups in college (for me, college wasn't that long ago, I'd done the right out of high school thing, then went back when I was close to 40 to finish). I'd be in a group where I was the A student. There was a student who didn't get it (just no capability) who on his own would get a low C or even a D, someone who was lazy (our F student), and a B student.
Now, if you'd average out A, B, F, and C, you'd get maybe a C, and this story says that over time, you'd do worse than that - yet all my groups got As on their work - even by my senior year, my groups were still getting As. There was never any time in my college career that I said "screw this, I'm willing to accept a C because someone else won't or can't work to my standards." Moreover, often the B and C student would let me know that they learned a lot working with me on my team - they became better, not because I carried them, but because I helped them. During one class, we lifted not only my own team (who really stepped up to follow my example), but because what we were doing was group presentations and our group was scheduled to go first, the entire class was lifted to a different standard. Two years later the professor wrote me - it was the best class he'd ever taught, and he gave our group's presentation credit, and in the peer eval forms, the group gave me credit.
It seems like many of these arguments are "we shouldn't help out the B or C student, because in every set big enough, there is the lazy guy getting an F, who is managing to pass his courses off the hard work done by team projects, some whining to the professor, and a last minute cram session with a tutor provided by the school." Yet, the B and C students really don't deserve to be lumped into the F group - and sometimes, they are B and C students because...well, there was the semester I was the B student on the team because my sister was going through chemo and I was time constrained with more important things and distracted. And we still got an A on the project, because other people on the team stepped up.
My household makes a lot of money - and we pay a lot in taxes. I've never felt like I shouldn't work harder to get a bonus because I'd lose half of it to taxes - I still get half my bonus. I don't know anyone financially successful who does. I do know people who will take the time trade (less money, more time) at a certain point, and have myself - but that's good for our economy, since if the work still needs to be done, you hire someone to do it to free up your time.