> EE to debug react state management ... easily pick up most of it after a week long crash course while training a performance engineer ... would take months

Isn't that mostly because as you go up the abstraction layer, tools and docs to teach yourself the tricks of trade fast are in abundance (let alone a popular layer like React)? Which inturn is likely a function of incentives and opportunities.

It's because the higher up the stack you go, tools become more declarative and literate. Calling sort is far easier than understanding the algorithm for example.