I suspect they got pretty good wages, insurance benefits and paid vacations they wouldn’t have gotten without the union...
Like they do at Nissan now without a union.
Insurance benefits are being cut, the pension has been frozen, wages have been stagnant, and Nissan has a two-tiered work force with about half of them provided by an outside contractor who is paying their staff about half of what Nissan pays their people. Those are the primary beefs with the Nissan workforce that I've read about.
Best way to keep out a union is to keep your workforce happy.