> Experiments show that transfer learning basically doesn’t exist, average people simply cannot apply principles they’ve learned in one context in a completely different context.

This is an exceptionally bold claim. Sounds dubious.

> Finally, many people have very successful careers in one field despite having a degree in a completely different field, which suggests that whatever people learn in their degrees doesn’t really matter all that much.

No it doesn’t. For that to be true you would need to demonstrate that, say, having an engineering degree does not influence likelihood or magnitude of success in engineering careers.

In reality there are likely going to be many recipes for success. Nepotism or social skills is one. Learned Competence is also one. Dumb luck is a third. The fact that you can succeed without such things does not mean such things are worthless