Why is it that the hardest, most backbreaking jobs have the lowest pay?

I recently started my second summer of working as a housekeeper for a local hotel for minimum wage, and started wondering why jobs with a great amount of manual labor seem to always have the lowest pay.

The lower the education required to do a job, the harder the work.
I once had a job delivering meat to grocery stores. It was cows cut into 4 pieces. Each piece weighed 120-250 pounds. You had to carry the stickey, greasy, BLEEDING side of beef with bones cutting into you, on your shoulder into the back door, of which was usually closed and then stand and wait until someone finally told you where to lay, or hook, the meat onto. I went back to school, then college at night, 1 class per semester, and graduated 9 years later! Now I work in an office with a view.

you're not the only one wondering about it, dude.
Because most back-breaking jobs are pretty much no-brainers. If you can stick with it and do a good job until you get something better, it's good training.
Brainpower is hardest though. Also, our society considers the positions you described to be of a lower position and status. After all, you really dont have to go to school to get hired in one of these places.
The top jobs are the ones that they can't replace... As sad as it sounds, they've got lots of people willing to work as housekeepers... but how many people are qualified to play football in the NFL (really qualified I mean)? How many actually get accepted to law school, then make it through... taking out hundreds of thousands of dollars in student loans? You can't find NFL players and attornies in the classified section...
It may be wrong, but it's life... the rich get richer and the poor get poorer!
That same question was asked by a laborer I heard about. The guy and his friend were down digging a ditch in the blazing sun. The boss was sitting under the shade tree, drinking lemonade. The guy went up to the boss and said, " Hey Boss? Why is it you get to sit in the shade and get paid the big money and Joe and I have to dig a ditch in the blazing sun for minimum wage? Boss looked up and smiled. He put his hand on the tree and said, "Hit my hand as hard as you can." The guy said he didn't want to hurt the boss's hand. The boss said not to worry, he wouldn't get hurt. The guy hauled off and hit, and just before he made contact with the boss's hand, the boss moved his hand and the guy's knuckles were busted all to heck. The boss smiled and asked,"Any more questions?" The guy shook his head and went back down in the ditch. His friend Joe asked him why they were sweating in the sun for minimum wage while the boss drank lemonade. The guy smiled and put his injured hand in front of his face. He said, "Hit my hand, as hard as you can..."
Do you understand now?
I Sooooo agree!!!! i guess u dont need that much educations 2 do it so since u dont have ur papers they dont feel the need 2 pay u.