>jump into architects or prod management but not the opposite way.

This has nothing to do with any intrinsic difficulty with coding and more to do with the industries penchant to rewrite everything every couple of years. The reason you don't see people who went to management become ICs again, is because you have to spend time learning the new, correct™, way to do read and write code.

From the constant API churn for something like React, or even the 20 million updates to write "modern" C++, someone who has had those minute decisions abstracted away will struggle to write code.