But, they aren't. Any traditional employment situation would forbid working multiple jobs at the exact same hours of the day. Any traditional "hourly" employment situation it would be completely impossible to even perform 2+ jobs at the same hours of the day.
But with gig work it's not only possible, but common. I would expect that if these drivers transition from contractors to employees they will be required to sign employment contracts which will forbid them from doing other gig work during their "shift." It remains to be seen if this would be a net positive for drivers.
Ultimately I think there needs to be another category of labor for gig workers. Dependent contractors.
It’s a terrible argument to point out some things that are different and use it as an excuse to ignore all the previous protections that were put in place.
E.g. Uber shouldn’t be allowed to hide the details of a job before the drivers accept them if they’re not employees
Perhaps the concept of a work shift shrinks down to the time between accepting a rider and when you drop them off?