But, if all people are smarter, that makes me dumber because I am no longer more intelligent than everyone else.
I think higher education is much better at introducing critical thinking skills in society than grade school is. Honestly, I think High School should end at the age of 16 (We'd save millions!), with college and/or specialty training to follow. Most kids have an idea of what they want to do at 16, and simple tests can be used to help out the kids who aren't so decisive. Critical thinking skills will be introduced sooner, and even kids who don't go to a College can receive specialty job training, such as electronics, sales, hair dressing, etc. This takes a huge load off of both employees searching for jobs, since they'll actually have experience, and employers looking to hire folks, since they'll know who has experience. For the underachievers, they'll be able to get an unskilled job and won't be any worse off if they'd spent another 2 years pretending to learn. From my experience, most of the stuff I learned in the last few years of high school were reiterated in college (Besides math - I actually had to take starter courses because my high school didn't even bother teaching me enough to get into college.)
It's a much harsher system, but one that would save money, and get people into the work force sooner. Kids will also live with their parents for a couple years while working, studying, or looking for work. This will have the effect of parents (Gasp!) actually teaching their kids so they can get their foot out the door. For less disciplined households, though, underage crime might be a problem.
I believe a similar system is already in place in Germany and Britain, but I'm not sure. America's system seems more focused on an older style of teaching rich parents' kids, who didn't really need special job training, they just needed to know some math and basic thinking skills so they could manage their parents' fortune when they grew up. Sure, an education is important, but America's is too general to give any special job opportunities. It's a pity, because it seems like a whole lot of work to make sure someone can run a register after high school.
As a side note, I'm all for classes that teach 'real world' stuff that kids may never learn at home but will be inevitable anyways, but the examples in the OP are fairly vague. Stuff such as taxes, how insurance works, money management, how to get a job, social skills, and physical education classes that actually require physical effort would be great boon for any child being sent out into the world. Now-a-days, it's a blind baptism of stress and innocence, all of which can be avoided with just a few simple lessons that parents rarely teach their kids.