One problem I see for junior developers is that there is so much more churn in tech nowadays. It's just about manageable for seniors who already know the basics to keep up, but as a junior it's hard to build good basics if you've already exhausted all your brainpower learning $JS_FRAMEWORK_OF_THE_DAY.

Seniors' resume-driven-development is (even if unintentionally) making it much harder for any newcomers to break into the field.