I agree with the lukewarm comment about having kids have some skin in the game, but also realize that economics have changed a lot over the last fifty years. It was definitely possible in the 60’s and 70’s to work 30 hours a week and pay for tuition and live frugally. That is not possible now except in a very few circumstances (like if kids live at their parents’ house and eat their food or if they have a scholarship doing the tuition heavy lifting.) You can’t pay for room, board, and tuition in $12 an hour.

However, I would also add that if your child is smart and hard working enough to get into a top school, don’t be that parent who thinks it’s good for them to work at the cafeteria at Stanford 30 hours a week while taking a full course load and competing with other geniuses who have family money. You can survive if you do that at SLCC or Utah or BYU or Ohio St., but you can’t if you are at an Ivy League school competing against Asian kids who speak four languages and play nine instruments and study physics for fun.
In that situation, school is your job and your hobby and everything else.

The last thing I’ll say is that in order to prevent complacent kids, just put proper incentives. I.e., if you maintain a 3.7 or higher I’ll pay full tuition, 3.3 you get half, and below that you get nothing (obviously this would depend on the difficulty of the school and major.) This seems like the natural consequences to me, because if you’re studying so hard to get good grades you don’t have time to pay for tuition, whereas if you are partying or slacking and get mediocre grades, then you clearly have time to get a part time job to pay for half or all of your tuition.