I simply want to add that, when you study labour needs, it seems to me you have to take wages into account. If an industry is offering inadequate wages and poor working conditions, it will find no one to meet its needs, except perhaps foreign workers who would have even tougher conditions in their country.
How can we determine whether there is a genuine labour shortage in a certain field? Is it only a matter of poor working conditions? Then we could solve the problem by improving working conditions.