@Tfmonkey I just thought of a scenario from my own life that would fit both of the categories of highly important/critical work that is low skilled. That being a summer job I did vacuum broom operating at a flour mill. It is absolutely critical to the operations of the flour mill (given how flour dust buildup can mean the whole facility exploding with just a spark), but it is a job that you can replace with nearly anyone, and therefore it is not a job that pays luxury wages.