Despite what some of our societies’ most dogmatic cynics believe, most people actually do wish to make contributions, learn about the world and each other, and help everyone satisfy their basic human desires and needs. Carrots and sticks don’t turn apathetic people into productive contributers, they just turn well-meaning humans into recalcitrant mules.
We've fallen into a false premise that ROI can be applied to everything. We don't even know how to determine ROI for education. We have ideas about it, and every few years we have new ideas about it, but rather than trying to hard to maximize ROI, we'd be better off just killing it by investing in those fundamentals. It's like raising a kid. A good parent doesn't give a damn about efficiency when trying to raise their kid. You just flood them with good examples, and opportunities to learn. Make people fight over teaching jobs, and give the kids more attention. As for bonuses, IMO they most effective when the job sucks and/or doesn't pay enough.
I work in sales and have a number of friends that do too. All of us have moderate salaries but have tremendous bonus potential. Some do "moderately" and others very well for themselves. I have noticed that there is no secret, increased concerted effort = increased results = increased pay. Most of my friends in sales positions wouldn't say it "doesn't pay enough" or that it "sucks". If you treat it like a craft, honed by knowledge of product and communication skills, you can do as well as any other professional and still have more time to focus on other things. This is off topic, but the problem I see with many careers (my wife is a doctor) is that they are all consuming. The people that have the resolve and capacity to be the best Doctors and Scientists are often the type of people that have a multitude of interests. To chose many fields of medicine or science means you must alienate your other interests. This holds no appeal for me. I chose my profession because it satisfies some of my creative desires as well as my completive nature and pays me well.. while giving me time to pursue outside interests to a great extent. Back on topic. -To say that they are "most effective when the job sucks and doesn't pay well" is just plain wrong. That's when they are the least effective.