Another thing to consider is the basic IQ requirements of modern high quality jobs. You don't need to be a genius to be a Doctor or Programmer but good luck fi

Another thing to consider is the basic IQ requirements of modern high quality jobs. You don't need to be a genius to be a Doctor or Programmer but good luck finding them with subs 80 IQ's (~16% of the population). It may have been more dangerous and paid less to build the Model T but it was also reasonable to send just about anyone to that type of work. Now add to that Illegal immigration which results in fairly intelligent people doing manual labor for low pay it's even harder for people that are a little slow to compete.