To counteract this and get the employees a fairer share of the value they add to a company unions exist so that the power imbalance gets evened out between workers and management.
Are people just a thing in a financial transaction where each side tries to get the most out of the other at the least cost? If someone thinks that then it's kind of a sad view on humanity.
This isn't "abuse", it's a free market system.
This is an honest temptation. It's not just about the company health. It prioritizes some employees over other employees.
It's more than optimizing expenses.
However, the vast majority of executive compensation is in the form of equity, and labor's demand for more cash will punish the stock price. Plus there really isn't that many executives and you can't squeeze them enough to cover the extra spend on labor.
A small difference in wages won't attract people from far away to move to a new location because of all the thing I originally stated and ultimately while there are some good benefits to manufacturing in the US it's hard to beat Mexico or China because the costs are so much lower there for labor. On top of that because it's a relatively low skill field the potential hiring pool is very large so there's little need to pull in veteran higher wage (and higher healthcare cost) employees from other companies.
You're also now looking at the company's perspective rather than the employee's. The fact that there are other industries is a benefit to the employee -- if you can go to college and get paid twice as much as a software engineer then some people will take that option (benefiting them), which reduces the labor supply in the original industry (benefiting the remaining people).
I still don't think you could/should get rid of the unions though.