I am working off the assumption that the parents in this fray want their children to grow up to be employable, or even to start their own businesses someday. If that does not apply to you, then of course what I am going to say does not either. But for those of you who it does apply . . .
In order to succeed in our capitalist society, you have to be able to provide some sort of good or service that other people value highly enough to actually pay you for out of their own scarce, hard earned dollars. The better a job you do at meeting the needs of and fulfilling the expectations of others, the more financially successful you have the capacity to become.
So it stands to reason that the sooner you start teaching your kids the value of fulfilling the expectations of others in their work setting (and school is your kids' work) the better a job you are doing of setting your kids up for financial success.
Does there need to be balance? Undoubtedly. Do you need to teach your kids to pursue their dreams? Of course. Should your children discover what they love and then make a career out of it? That would be great.
But even your dreamest of dream jobs is going to have substantial doses of work that needs to be done whether you want to or not, on your customer's timeframe, not yours. That is life.