Any place that is replacing junior devs with AI is probably going to really regret it when they have no senior devs in a few years. Being a junior dev in a team is kind of like an apprenticeship. You learn the trade, but you also learn the shop. Then when the senior dev moves on, you have all that knowledge and can step into the role of senior dev. If a team decides to not have junior devs anymore, then they’ll have no one to take over when a senior dev leaves.
So the answer is yes, it is already replacing junior devs, but that’s only because management hasn’t learned how bad of an idea that is yet. Ultimately, it will cost them more through losing foundational team knowledge.
You also have to hold an AI’s hand the entire way through coding something, whereas you can kind of just let a junior dev go do their own thing, and eventually they’ll probably get it right. An AI “agent” tries to hold its own hand, but that doesn’t seem to work out usually when I’ve tried it. It starts making changes that are really bad, then just seems to always double down and eventually make a huge mess.