>>>>Most rich countries heavily subsidize young people's education, including travel and service.
That's partially true. The reality is that most rich countries (That we are talking about) purposefully make young kids stay out of the workforce, unemployable, until their very late 20s pursuing "well rounded people" education that is not useful and leads nowhere but extended unemployment. They have even culturally codified some of this (see: erasmus) This is how they keep unemployment stats low, said countries classified every u-26 as out of the workforce and not looking for work.
In contrast, the US is at least minting some U-21's that end up becoming millionaires, plus by the time most american grads hit their 30's , the majority have a very upward career trajectory, even bought 1-2 large assets.
Meanwhile, their economic peers outside of the US are still at their first job, trying to make ends meet. They could only dream of buying an apt, let alone a house.
You can have differing opinions on what this extended education model provides, whether its more/less useful vs USA, and what it means for social cohesion and peace (by keeping a very large contingent of young kids hooked education freebies). However, it is not up for debate that the limited economic opportunities connected to extended education are severely diminishing the economic prospects of those young kids