No. I know that there are a few barriers keeping people near the "minimum worth" level:

1. education

2. language

3. physical/mental inability

What are some other ones?

Ready availability of competing labor.

Minimum wage jobs are frequently difficult and labor-intensive, but the individual workers are replaceable. The idea that pay rate and effort required are perfectly linked is what I'm contesting.

You are right. I was wrong to link "hard work" and "pay". I should have linked "skilled work" and "pay".

Don't people work hard to become more skilled though?

That takes another scarce resource, time.

(And frequently money.)