You mentioned two aspects of career path as programmers in your post.
For the first one,I agree with you, actually we only need to master one skill in present-day society to help us survive even acquire higher income instead of by learning a pile of technologies without being proficient at them.
For the second one, about education background,I favour partially what you say,but I have supplement.
Although you can join the famous or briliant or first-class corporation as well as peers with better education background if you can make great efforts or with smart brain to master a technology, you probably found those peers can reach the same objective with less time or less efforts.
Coz most of big corporations admit the value of education background as they can also accept talents with poor education.