There is of course the possibility that AI gets good enough that even senior engineers won’t be needed, but at this point it seems unlikely. My reasoning is that even expert humans make mistakes, which is why we need other humans to collaborate and check each others’ work (which, if you think about it, is a source of a lot of the processes and bureaucracy at companies; trivial example: code reviews.)
So even if AI gets to the level of human experts, this dynamic will not change... unless we hit ASI, where the AI far exceeds human capabilities. At which point we’ve hit the singularity and all bets are off.
Short of that, however, human experts will be needed, which is why programs like this are needed: to future proof against the short term economic pressures to minimize junior workers which will impact the long term pipeline that produces senior experts.