I have several hobbies that are popular with kids (mountain biking, rock climbing, and some others).
I can assure you that there are plenty of kids with more time than I have to dedicate to these hobbies at every popular spot I go to. Many of them are ambitious, smart, and working toward top universities, too. It’s actually fun energy to be around.
The parent comment about students getting up at 6:30AM and working 15 hour days is highly unusual.
The fact is that they aren't working extra, not for a job anyway. The extra work comes in the time making dried beans instead of buying canned, in repairing stuff poorly, in shopping around for a doctor that takes the state health insurance or an affordable option if you have none at all, in taking busses (if they are available), and other unpaid things. Your child will be lucky to afford the activities that gets them a 'good' education, especially if they have to work.
That is exactly OP's point: for OP, if a child's "working hours" includes university prep and resume-padding sports activities, then an adult's "working hours" includes housework, grocery shopping, dealing with insurance and taxes, and commute/family chauffeur time.
And for the record, I had to work less to get to good school back then.
Pressure makes diamonds, but it also crushes everything else.
Overcoming hard times absolutely made me a better person, but as I've grown I've seen many examples of the fallout you're referring to. Sometimes people just break.