Birchy Birch!!!!
I think you are right and wrong. You kind of make one point, and then segue into another one.
Note, this is coming from an honors/AP student so, of course, it is biased. First, you said that the ranking sytem leads to the educationally un-fit losing out through a process like Darwin's natural selection. Now, I agree this is what is happening. The thing is, it would happen anyway. Many of the educationally unfit are not willing to learn. That is their problem. They will skid through highschool in crap classes and not go to college and get a shitty job. Many, not all. But, what does public school need to do. The smart will rise, but it isn't only the smart. The people with the desire to work will rise. My best friend is one of the smartest dudes I know. Yet, he is hom during school, using online school because he couldn't cut it in actual school. Smart as all hell, and too lazy to move forward. Now, the girl who we predict to be our validictorian is average. Completely average. But what does she do? She works her ass off. She studies every night, she goes that extra mile, she does everything. If some poor and kinda dull kid wanted to succeed, he could. It is just that he needs to work hard, and that, is something he/she probably isn't willing to do.
Your second point is talking about public school basically spitting out people to equip them with jobs. No ambition, no creativity, no nothing. I agree. But how do you stop it?
Now, with the curriculum. Like icy said, the curriculum of schools is so tight, you can rarely ever venture out to what you might need to learn to make it fun and cool. Many times, we, as a class, and an honors class mind you, have needed to keep going to keep up with curriculum, leaving many students behind. It has gotten to a point where it is no longer "they need to learn this, this, and this" It has become "they need to learn this, this, and this, using that, that, and that, at this time, this time, and this time" I have seen teachers curriculum plans, and trust me, it is like that. One could easily say that in order to end it, you just need to stop, but then you face a problem of not everyone in a class or a school, or a district, or a state, or a country is equal. You might have one class end the year at chapter 4, when another ends at 12. This entire thing also brings back point 2. This is turning all students into one of the same.
So, those are my points, sorry if they are kinda scattered.