Corporate greed can only be stopped by disallowing the divide and conquer strategy they employ. Individual bargening against large corporations only works if the employer works in good faith. So when the relationship was good they could have also formed a union and work together to have a fair footing if anything changes in that good relationship. The employees as a group missed that window and now that it’s needed the framework for collective bargaining is not there and individuals are left holding the bag.
Unions should not be demonized as a bad thing or punishment for the employer, it is a counterweight to the corporate machine if it ever shows it’s ugly head. Good employers have nothing to fear if they work together.