so what's the cause ?

maybe there's a cultural failure - where if we consider a 'generation' of devs to be in cohorts of 10years. they have failed to pass knowledge down. hence why the wheel keeps getting reinvented.

every industry grows & refines itself by knowledge & skill getting passed down. software is the one anomaly. & right now with LLMs they're tryna kill juniors.

which boils down to 'culture'