Workers in the US are free to get together and argue (without a union) for a group or general pay increase. Workers can as a group walk off the job. Workers are free to quit at any time.
Voting with your feet is the most democratic thing we have.
And employers can ignore workers or fire them. If the company ignores too much or fires too many, then the company will suffer.
IME, that works much better than using the law to privilege either side.