My impression is that this is a problem of the companies own doing: In many cases they are unwilling to hold employees (because young employees are "better", so

My impression is that this is a problem of the companies own doing: In many cases they are unwilling to hold employees (because young employees are "better", so just fire them when they get "too old") and unwilling to give employees their fair share of the profits i.e. pay raises are almost always lower if you stay at a company than if you change. This two parts lead to people changing companies far more often than "back in the day" and now companies say "We cannot train people! Then our competition will just take them when they are trained!" - Yeah, because companies don't value their employees enough. And now we've come full circle.