At which companies? Amazon? Google? Target? UPS?
It's the massive employers with huge legal teams where you need a union so you can fairly negotiate with their massive legal team. The subject that started this is unions at Amazon. Not negotiating with your local restaurant about how much they will pay you to wait on tables.
What was the nature of the change? Did you get additional healthcare benefits? The kinds of things that unions negotiate about? Or was it something trivial? The details matter.
If workers can effectively negotiate as individuals then why have wealth gaps skyrocketed in the USA as unions have weakened? The lowest wealth gaps in US history were when unions were the strongest. Wealth gaps in Germany are much lower and unions are much stronger. All evidence points to you being wrong about individuals being good negotiators at getting a bigger share of the pie. And it's just common sense. The idea that most of us are qualified to go up against a big and highly trained legal team is laughable.