At least in the case of DoorDash, they have an arbitration clause in their TOS that effectively quashes any attempts at a class action.
Hopefully one day the US justice system will wake up to the fact that allowing companies to opt-out of the main mechanism preventing them from engaging in this sort of petty-crime-at-scale is not a good idea, but until then it's what we're stuck with.
You can individually opt out of the arbitration clause, the problem is finding a critical mass of other people who opted out within the opt-out period.
The Department of Labor didn't sign no arbitration agreement with DoorDash, and they get a raging hard-on for wage-theft cases. Management stealing tips, where people who didn't do the work but receive a portion (or more) of the tips are slam-dunk cases for them.
Hopefully one day the US justice system will wake up to the fact that allowing companies to opt-out of the main mechanism preventing them from engaging in this sort of petty-crime-at-scale is not a good idea, but until then it's what we're stuck with.