Which is unfortunately very true. I think, that in a healthy organization such kind of mentoring requires extremely well defined boundaries and rules. Can I spend 1h of my time explaining basic stuff to a junior, who will then be able to finish his task in 2h instead of 8h? Mathematically this is a win for the company. But economically, maybe that junior dev should be fired.

That's the problem -- except in the rare type of org that thinks past quarterly or annual results and thus values training up a pipeline to be the future seniors -- economically speaking, all the junior devs should be fired, and the simple tasks they can do are the same set of tasks that can be accomplished by a senior at the helm of AI at 10-50x the speed.