As an industry we can't just cut off the pipeline of future senior devs.
This is the fundamental contradiction of LLMs. The promise today is that the tooling can largely replace juniors, and honestly that may be true.
The hope behind that promise, though, is that the tech will catch up with senior devs before the pipeline dries up and that we have found a sustainable social and economic model before humans truly aren't employable at any meaningful numbers. That hope seems ill placed to me, but I guess we'll see if we develop such skilled LLM or similar tools at all.