The "sick feeling" I get (and I find MLM fascinating for many reasons) is that I know 99% of it is just trading on hopes and fears.
No reality, just hopes and fears -- which may or may not match up with reality.
When I think of it as a game, then everything's cool. But the problem is that these games often have real-world costs for people....
Anyway, my belief is that we're less likely to do harm if we engage in those pursuits which bring us joy in themselves. Not acting out of hope or fear, but just joy.
I know that sounds naive and many arguments can be raised against it...but it's a hunch I've got and while I don't have the details worked out for myself yet, I feel like that's the way to go: instead of wondering about how I'm to make money, I'll determine what brings me most joy ("profit and efficiency" in your language, in a sense) and let the money-making take care of itself.
After all, it's possible to not make much money as a lawyer, doctor, accountant, or entrepreneur -- but if you enjoy most if not all of the actual daily activities involved with each profession, you'll at least have "covered your costs" and "come out ahead" with a small "profit" (joy!)....