Not to imply a parent is obligated to pay, but parents aren't really obligated to pay when their kid is 18 either. It shouldn't affect retirement savings, unless spending increased in the intervening years and ate into the investment they had planned to make in their offspring.
Even though we have saved for my youngest to go to college we are expecting her to apply for many merit scholarships and we expect her to help with some expenses using summer internship earnings. The more she contributes the better her chance for ownership over the college outcome.
In the case described, I somewhat question the motives, since (s)he described "screaming and yelling" over the choice of a different career, which seems to imply they sought a degree of control over his/her future. Keep in mind both were Ivy League PhD's. So perhaps they didn't see it as money set aside as an investment, but more as something they'd donate with conditions. Not wanting to pay could also be a way of punishing their children for not pursuing the career paths they'd wanted.
The problem in this case, imo, is that there wasn't an understanding between them about whether paying for college would still be an option in the future. Since that's an attitude that will differ from family to family, it doesn't seem unreasonable to think a given family would need to work it out for themselves ahead of time.
>Some might have alternatively chosen to invest the money in their children another way, like using it to start a business or starting a stock/bonds portfolio.
I strongly support this for families where this works out. There is never one model fits all.
I don't see parenting as providing your kids with everything. I see it as provide your kids with the tools they need to be successful in life. Sometimes the hard way is the better way.
When a child is ~26 then hopefully they can be on their own.
I'm not sure how you can judge me self centered when I provided for the education of one child already and am ready for the 2nd one. I was pointing out that there are many dimensions of being a parent and providing for college.
So from a practical standpoint cash flow is a consideration. From a dependency standpoint isn't eight years long enough for you to mature beyond financial and emotional dependency?