That's a possibility. Absolutely.
I would counter argue that if you make it optional it gives them - options.
Anyone will tell you, kids LOVE to learn. They love to ask questions and explore. But 'you have to' makes it a chore, takes the fun out, and naturally no one likes that and they rebel.
No one wants to learn with a gun to their head.
The schooling system just isn't fit for it's purpose for many children. How can people get expected to learn in a place that makes them feel forced or unsafe, for example?
Look at the rates of reading comprehension dropping these days. The system doesn't even work.
And IF kids they opt out when they are young, they may opt in at a later point. They could train at any point in life that suits them. Rather than scoffing at 17 year olds who fail exams and can't go to uni. Perhaps they take a class at 15 and that's one grade and another at 19 and there's another. Whatever works for them.
There are theoretically masses of 'manual jobs' going. That's why we've had to increase immigration. Not to mention the arts and various entrepreneurial possibilities. Plenty of people can't do high brow jobs already....does that mean their lives have no value? That they have nothing to contribute? Just because they didn't pass classes as kids?
The point is radical change always creates new issues to solve. That doesn't mean it isn't necessary.
But I'll bow out now as we're derailing the thread a bit. And clearly I can bang on about this subject indefinitely xD