It's quasi-ageism, I guess, in that junior level workers are difficult to accuse of stagnation. So although junior level workers may stagnate, it may be assumed

It's quasi-ageism, I guess, in that junior level workers are difficult to accuse of stagnation. So although junior level workers may stagnate, it may be assumed that they didn't yet. I've seen devs in their early 30s as victims of this stagnation assumption (10 years in some traditional industry).