Do most of these things really take 10+ years to "figure out" though?

> its much more about connections and office politics than hard work

Whether or not it's "much more" depends as much on your employer and your field as anything else, but nobody should reasonably expect that employment is a pure meritocracy where your work product is judged in a vacuum irrespective of how much people enjoy working with you or how much objective (and subjective) value you can bring to the business.

> there is really no job security, and they could be one layoff wave away from unemployment

Why would there be? Nobody I know is signing employment contracts or working in Civil Service positions.

> its much more about face time and spending long hours at work rather than actually being productive

This is entirely dependent on employer. We have a handful of developers who spend maybe 25 hours a week physically in the office but they are as productive as anyone else.

> the majority of their work, to their surprise is not actually that important or necessary

This will depend heavily on industry, employer, project, and seniority. If you're an entry level dev and not particularly skilled in what you're doing yet and new to the industry you're going to spend a lot of time learning which will pay dividends 15 years later but is not objectively important to the specific project you happen to be working on.

> its important not to take too much vacations, because its an opportunity to loose the little work they have to someone else

I have never seen or heard this in any of my jobs, with the exception that a lot of the folks recently from India that I've worked with seem to take it as a point of pride that they let a huge chunk of their PTO expire every year. But I think that might be cultural as none of the Indians that I work with currently who have been here for a while (5+ years) do that, they use all their vacation every year just like everyone else.

> they are never going to get [paid] the true value of their work,and that is almost the definition of being an employee

Well a business doesn't exist if it pays out 100% of profit to every employee. It's actually pretty easy to be a contract developer so if someone wants to handle all the administrative nonsense in order to squeeze out a few more thousand dollars a year they can do so. I've been underpaid and overpaid (overpaid is certainly better) but nobody's ever tricked me into earning less. Negotiation is a thing, if you can prove there is an extra $30k in value in a position/promotion, prove it. If it makes business sense to pay more for talent, start a business and do it. If it actually makes a difference, you'll have a competitive advantage.

> its all a system of serventry not too different from the medieval relation between master and servant

This is objectively false and weakens all of your other arguments (some of which are reasonable).

> its a system that they are being grinded through and discarded, and that they are condemned for life to making someone else rich, never getting a chance to [truly] [fulfill] their dreams and ambitions

If anyone ever told you that the purpose of employment is for you to "truly fulfill your dreams and ambitions" they're an idiot, a liar, or both.