your wage is a price, just like the price of hamburger. the price an employer is willing to pay is related to the value of your work to the organization.
one of the things unions tried to discourage was automation. the computer/chip revolution settled that issue. if a machine could do a job cheaper, guess what.
interestingly, union management was more willing to protect the ones who were left than try to protect those whose jobs were eliminated. at one company i
once worked for, management offered to reset pay levels to save some low seniority jobs. the union membership turned it down.
