As long as there's no decent form of vocational education, training in-house is a huge investment. You can only properly train one junior for every three to four seniors before it becomes disruptive.

Many companies that have already made the mistake of hiring too many juniors in an attempt to deal with the shortage, and have suffered the consequences (huge drops in quality and productivity, and in the worst case, seeing the experienced seniors they did have walk away frustrated).

Where education fails, major companies like Google and Facebook should take the responsibility for training juniors. Instead they spend their fortunes strip-mining the market.