1) Not everyone has the aptitude, desire, or willingness to get a highly technical job. Those people should not suffer.
2) The pay of all positions are based off of supply and demand. If everyone has a degree in radiology, the pay for being a radiologist would drop a lot. This can be seen in tech. Tech support positions in rural areas require bachelors degrees, yet pay less and less per year($12/hr in my city).
All of my experience, every success of outreach programs bringing new people to tech, everything we know about the distribution of IQ suggests that it's not the case. There is plenty of room in the future economy for more knowledge workers and we shouldn't be making the assumption that people should let their mind rot doing work better suited for machines.
Maybe not. About half of new US college graduates take jobs that don't require a college degree.
We may need fewer "knowledge workers" as AI picks up. We need far fewer paper-pushers and middle managers than were needed in the 1970s. Sales once seemed safe, but consider Amazon and Esurance. That's what the decline of the middle class is all about.
All of your experience and every success? What about the failures? What about coding bootcamps that result in failures?
You're going to need to cite at least some sources when you say that it's possible to teach _everyone_ a highly technical skill.