Answer: Because they're employers, who have to be scapegoated (according to "fair trade" doctrine)
The fact is that employers seek to keep running costs down.
Which is what they should do. Whereas "fair trade" tries to impose higher costs, like wage levels higher than that necessary to attract the needed workers. You're showing how "fair trade" is worse than "free trade" because it drives costs up higher than necessary = higher prices = higher cost of living for all.
It is not in their interest to increase wage rates for any reason other than to attract and retain key staff.
Yes, to pay the minimum increases required to keep the operation running at maximum performance level, and no higher labor cost than this amount. E.g., to attract or retain the highest-performing producers/wage-earners, at only the level needed for this, meaning lower levels for those who are the easiest to replace, e.g., those higher-paid who can more easily be replaced by someone or something which could do the same function at lower cost.
It's not in the interest of a business to maintain market value incomes for workers and . . .
No, IT IS IN THEIR INTEREST to pay market value. Your stats have shown that they have let wages stagnate ONLY for those of lower market value, which might be a large % of the workforce, as those wage-earners' market value has declined, as they have become less necessary and more replaceable. So business has maintained the market value for workers, meaning in some cases (many/most cases perhaps) even reducing the wage level as their market value has decreased. So, "to maintain market value" means in some cases
reducing the wage (as the worker value decreases) as well as increasing it as the worker value increases (perhaps for a small % of the workers in some cases).
. . . and individual workers are most likely not in a position to ask for pay rises.
There are millions (billions) of individual producers "not in a position to ask for" higher compensation (from their employers or from their customers or whoever pays them) because they're already paid their market value, even though probably 100% of all producers of any kind believe they're worth more than they're paid. Bummer!
CEO and executive salaries, of course, are a different matter.
Maybe. This might be a problem in some cases. And there are some rich celebrities, entertainers, pro athletes, etc. who are overpaid somehow. Maybe we can solve this if we first get cured of our obsession on employers as a class to hate and scapegoat.
A double standard if ever there was one.
"double standard" = illogical. So let's find a LOGICAL solution for a change.
Some kind of higher tax on the super-rich is the way to fix it, not scapegoating all employers. Like the sweatshop owner, e.g., many of whom are struggling to survive.
A logical solution (in contrast to a "double standard") is one which targets the problem and fixes that, not one which eliminates some viable jobs, reduces needed production, and punishes all of society by driving up the cost of living for everyone.