I think seniors know enough to tell whether they need to learn or not. At least that's what I tell myself!

The thing with juniors is: those who are interested in how stuff works now have tools to help them learn in ways we never did.

And then it's the same as before: some hires will care and improve, others won't. I'm sure that many juniors will be happy to just churn out slop, but the stars will be motivated on their own to build deeper understanding.