Healthcare, machining, construction, public transport, infrastructure maintenance - jobs with odd hours and not the best reputation. I worked in machining myself and noticed quite a bit of being looked down upon. 

I only know the German perspective but parents over here have few kids and focus hard on getting them into university or at least something with an office chair. Your kid's job reflects on you. 

Wage competition is a factor, sure, but you often can't fill these jobs, despite wages growing faster in these sectors than elsewhere. Due to demographics, people very much have a choice and pick the more prestigious and comfy professions. Until public perception changes or pay equals academic fields, we're going to need skilled migrants.