For example, years ago I worked for Illinois Bell Telephone in downtown Chicago. The company was represented by the International Brotherhood of Electrical Workers. Employees had the option of joining the union, but if they did not, they were still forced to pay union dues but they had no representation. Illinois is obviously not a right to Work state.
I currently live in Arizona, which is a Right to Work state. About the only union members you will find here are Federal government employees.
Right To Work - Arizona is a Right to Work State
There was a time when unions were needed because workers were abused by low pay, dangerous conditions and long hours. That time is long past because we now have hundreds of laws that protect workers from abuse. When people are given a choice, most do not chose unions.
Unions have a long history of greed and abuses that far exceed those of employers. You may not realize that most unions in the USA are still run by crime syndicates. I went to school in Chicago with many of the kids of crime syndicate members. Today, quite a number of the guys I went to school with are managers in the Chicago unions. In the 1950s, most of the crime syndicates went "legitimate', which resulted in their takeover of unions and most major shopping malls. That is not an opinion. It is a fact.