Earlier quoted context omitted.
So what are the long term risks when senior staff leaves and those need to be replaced with new seniors that have never seen the existing work vs. promoting younger people who knows the projects and practises?
These days normally what corporates do is bring in people from abroad who have the skills. The idea that companies would seek to train up domestic workers if there is a skill shortage is outdated today – even if theoretically this might be good for the domestic workforce. It's just cheaper and easier to import the skills needed.
But maybe my comment was not noting every discipline. I was mostly thinking about software development.