Require walmart to pay each employee twice as much, and they will probably fire half of them, train the remainder better, and have customers bag their own groceries. Same total labor cost.

I see no reason to believe this would happen. May I recommend a post on the subject?

the people fired by walmart in this situation are not really worse of

Oh really? Do you think Wal-Mart employees agree with you on that point? You're basically saying that there is no reason for anyone to work at Wal-Mart. This is... empirically wrong.

actual jobs

What counts as one?