A more common situation are junior developers who are embarrassed by mentoring, and so vocally push back with anger that you would dare violate their ego. This is a bad cultural fit that needs to figure out their place in the universe or get the hell out.
Perhaps a blind audition would to for tech what it did for music: there aren't any "junior" orchestral musicians. If a musician makes it through to win the job (no matter their age or time spent as a professional) they don't need any mentoring. Winning a blind audition against 200 highly qualified players who are desperate for paid work and who went to Juilliard too (or the comparable) affords the winner instant respect on the job. It's only the "Michael Phelps" who make it through in orchestral music and everyone knows this. No intelligent musician already employed by that orchestra would ever think they could count on winning another audition in that orchestra or any other. With every passing year, employed players fear having to win their gig again against those who have spent months doing 7 hours of orchestral rep practice and nothing but. It is similar to whiteboarding but allows for no errors in a winning candidate. It is just too competitive. I suspect those who fear a blind audition in tech fear that their main/only real qualification is culture fit. Perhaps they fear they would not win in a skill-based audition. Every player does need to adjust to a new band though. It doesn't take long for a musician at that level. This isn't remotely the same as mentoring. Musicians don't get paid when they need mentoring like swes do. That happens in the practice room and at school and in apprentice programs which the musician pays for.