@lightningcloud He's means of those surveyed, 70% of children consider themselves people who refuse to give up, but the numbers were far lower for the adults, meaning the adults responded they're willing to quit and give up sooner than the kids are- there's a greater cynicism with adults, willing to dismiss effort as futile. He basically presumes that's just normal and to be expected that wide-eyed idealism begins to fade as you get older.
He then segues into a related but tangential thought about kids being raised with the standards and expectations you would have for adults, as it's often a case of parents trying to push kids to things they couldn't have or accomplish themselves when they were young. He's not implying malice for what it's worth, just that it's natural for adults to want for their kids what they couldn't have but sometimes that ends up putting too much stress and pressure on the kids, who already have enough of that on their own during these developmental phases while they try to figure how who they are.