First off, I think it's worth noting that the current system of motivation, based on grades, is hardly better than straight up bribery, it's just that the theoretical rewards of the "bribe" (good college, great career, etc.) are so far in the future that they're pretty much invisible to most of the people in the system, except for the truly pathetic worry-wart-weiner-dogs that actually change their actions based on potential ten-year-hence consequences as high school students (which, I realize, is a category that many of us fall into, and there's probably something wrong with that, but now's not the time or the place...I was one of them, so I'm not going to cast stones).
I think rather than trying to bribe children to go to school because they hate it they should instead concentrate on making school actually interesting.
And I think rather than trying to bribe adults into doing work because they hate it it would be fantastic if we could try to make it interesting instead, so they would want to do it without compensation.
Of course, failing that, we have to pay them, because it's more useful to have a person do a dollar's worth of work for a "cheap" reason such as money than it is to keep the dollar in our pocket. Doesn't matter how nice it would be if the person really desired to do that work of their own accord, it's worth more to us to pay them than it is not to, so we do it.
Where's that analysis here?
From my interactions tutoring the hideously under-interested youth of America, at least the rich parents that care about such things would almost certainly be far better off (dollars and cents-wise) paying their kids a nominal wage to do their f-ing homework than they are paying me $80/hr to sit with them and force them to do it - even if I am there to answer the occasional question and review the material in a (hopefully?) more comprehensible way than the teachers might at school, in my experience the real gains are simply achieved by forcing kids to think about the topic for a certain amount of extra time every week, which they typically would never do on their own.
Basic reading, writing and arithmetic should be compulsory but let kids choose whatever they want to learn after that.
I'm all in favor of that idea. But you may underestimate the extent to which we're not even covering reading, writing, and arithmetic the way things stand. As educated people we tend to assume that everyone else is at least in the same ballpark as us, but look...those comments that you see all the time on YouTube, and chuckle at, assuming they're written by non-native English speakers? They are, in fact, pretty close to the average quality of the prose you'll get if you ask an average classroom of American students to write an essay.