Or are you suggesting that you would wait around and be homeless for 4 years until someone local built up enough training and experience in order to build your house? If you're going to suggest that you would wait and "live somewhere else", I would point out that people who are trying to hire, for example, nurses, often don't have that luxury. If they wait 4 years, they'll be dead.

No one is suggesting that high skill work status are used for people with no training or experience; they explicitly require training and/or experience in order to qualify. If think you're proving my point; if you need to hire someone right now, and there is no one available locally to do it right now, then there is a shortage, and you need to look outside of your local market.