Earlier quoted context omitted.
"When the tech world moved away from me (doing mainly embedded C for the last thirty years might not have been the best idea for my career)" Strange, why do you say so? We live in the era of IoT and everything has at least one chip inside them. I also do system/embedded programming, but never felt the lack of possibilities to advance my career.
How did you get into doing system/embedded programming?
I succeeded and even trained someone else how to do it. When we started, he didn't know C all that well so I split the drivers into hard and easy parts and gave him the easy ones. We wrote about six drivers together. I made his parts harder and harder until he was able to write a driver on his own.
Perhaps I haven't been reading the right software architecture books but it seems to me that very little mention is made of changing the design to suit the ability of the individual programmers, the way band leaders like Duke Ellington and Glenn Miller did with their arrangements.