Actually, Unions Bring Wages Down.
The Much less productive Union Shop, where productivity and Quality are discourage, where People are promoted simply on Time Served as compared to merit means that the Company is Much less profitable there by much less able to pay its Employees well.

In a Merit Shop each person can be compensated in proportion to their skill and promoted on their productivity.

In a Union Shop All get held down by the skills of the lest productive or lest ambitious employee.