What makes you think the worker doesn't wield enough power? The worker is actually in a better negotiating position than the company. If the worker decides to go work somewhere else, they lose nothing unless they decide to take a lower paying job, and likely can even land themselves a better paying job.Fair enough. I'm all for better unions. Don't think it will happen until the american worker wields a little more power. Job relocation has been the last nail in the coffin for that as near as I can tell.
The company, on the other hand, has to pay the people in HR to process each new employee, then they have to train them, costing them not only the money they are paying the new hire, but also the money they are paying the person training the new hire.
In the end, it generally ends up costing them more than it costs the worker, putting the worker in a position of relative strength.
Most workers are just too non-confrontational to demand a raise, and too lazy to go looking for other job opportunities on their time off.