So your original point is stupid. Americans can do ANY low level job there is no labor shortage at any level.
I would think there are lot of jobs that would require vocational training or at least an apprenticeship program ... for example welding, plumbing, carpentry, auto mechanic, a/c repair, radiology tech .... just off the top of my head. There are probably thousands of jobs that would require some amount of training ... but not necessarily a college degree.
Many jobs where THEY SAY you need a college degree you really don’t. That says nothing about a labor shortage either way, which is a separate issue. We don’t have a shortage of people who need a full time job, that’s for sure.