Is there a natural selection class society work force?
You can read and hear media programs on how if parents teach their children to read before their children first attend school, children are often more successful, achieving higher grades than parents whom allow schools to completely educate their children.
Parents from a working class background doing exhausting work, needing few reading skills that are often too tied, have poor language skills, feel their education was pointless, could be less likely to teach they're children how to read before their children first attend school.
Parents: having achieved professional degrees; being in middle management government or corporate skilful employment, would value they're education that put them in such valued employment.
Children of hard working parents will end in similar employment while parents realising children need to read proficiently before their children first attending school, such fortunate children will often succeed to obtain desired employment.
Is there a natural selection class society work force?

There is no place for comparison, because we are all born with different duties - some must work their muscles, others their brains. For one to do that which is unsuitable to their nature, feels as torture. Though exceptions exist, we are normally born in such families that are more likely to support us in fulfilling our particular purpose for this particular lifetime.

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It is far better to discharge one's prescribed duties, even though faultily, than another's duties perfectly. Destruction in the course of performing one's own duty is better than engaging in another's duties, for to follow another's path is dangerous.
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Bhagavad Gita, 3:35

http://vedabase.net/bg/3/35/en
http://www.bhagavad-gita.org/Gita/verse-03-35.html

When someone in authority states “society needs a skilled workforce” the skills often seen are truck drivers, brick layers, road makers and road maintenance workers. There are far more manual labourers having limited thinking skills needed to move stuff, drive buses, serve coffee, cook fast food, pack food store shelves, be a checkout chick. Checkout chicks only need to swipe items over a bar code reader to perform they're employment tasks... There are very few decision making and skilled professions compared to an almost nil skilled repetitive workers needed in a modern workforce.
So why are children trying very hard to get those desired grades when in most instances very little usable school learnt skills will be used?
One of my theories is education is a natural selection process that successfully removes from governing authority the task of dealing out hard working employment for many people and easy pleasurable work for others. Governing authorities don't care within the working class who does the hard work and who does the easy work.
If some governing authority chose who does what work, hard working employers would complain and most probably go on strike for move money. The natural selection bad education process allows poor education graded workers to believe educational grades chose they're fate.
If you've seen the first episode of Futurama, Fry gets embedded with a micro circuit chip that stops Fry from performing any employment other than delivering stuff for the rest of Fry's life.

Why are students with no desires for skilled professional employment being forced to try they're best for no beneficial purpose?

Yes I also believe the more competent kids, or those with some help at home, get better attention from teachers, even if not intentionally.

It does have a lot of luck involved. Our eldest wanted to be taught, & was reading & writing before she went to school.

The second did not like anything that looked like a lesson at home, but had the same great older teacher for his first 2 years. She chucked out the new trendy stull, used older methods, & had all her kids doing well.

The third copped a young lady fairly fresh out of her DipEd, brainwashed with all the trendy BS. Very few of her class were reading after a year, & ours would not have been, if we had not stepped in at home.

Good teachers are so important to whether they keep on learning. It really is great to have a son who by age 24 not only thought he knew more than his father, but in some areas actually did.

"So why are children trying very hard to get those desired grades when in most instances very little usable school learnt skills will be used?"

What's wrong with wanting a good education? Being a labourer (or not wanting to work in a corporate office) doesn't automatically mean the person is stupid or doesn't require a good education.

Having abroad education and being generally knowledgeable allows a person to mingle on levels. Quite often the 'menial labourer' has more common sense than the best academic.

Being smart does not equal educated.

I fear there is already a dumbing down of society taking place through our Western world education systems, which used to be outstanding. Advocating "you don't need an education if you are only going to be a labourer" will hasten the dumbing down.

If you need proof the dumbing down is already effecting people, just look how many think the Fast and Furious movies are entertaining.

SBS1 television PBS Newshour during 2010 to 2014 presented many presentations on USA education. With social concerns of school students poor education. In one USA district, an Asian American woman was given the task of improving the grades of poor performing students. The woman's solution was to make teachers responsible for student grades under threats of teachers losing they're employment. After a period, a number of teachers and headmasters were said to have been replaced.
What does a teacher do? I conclude, in high school aged students USA equivalent classrooms, teachers would be bullying, threatening, demanding already mentally stressed students to perform all educational department authority tasks asked of them. Teachers and headmasters getting parents to bully they're children into doing all their homework. Mentally stressed students hating education, being bullied by teachers and parents will learn to hate anything that feels like learning education in they're long working futures. The resulting example to what happens to students' personality can be seen on Dr Phil. Dr Phil shows captured video images of angry teenagers arguing with their parents, Dr Phil asking young teenagers if that behaviour needs to be corrected.
School students with excellent pre-school reading skills allow teachers to be soft on they're students. Teachers knowing that their students will do well on tests. Low levelled mentally stressed students find simple memory information with less mental stress traumas attached, easy to remember, which is why I believe low stressed children easily succeed in life.
High levels of mentally stressed traumatised school students hating anything that feels like learning end up as truck drivers and other similar low skilled employment.