neither do i. all of the on-call folks I know must respond to pages; they don't have the option to pass on them.

that's just the existing on-call model. it's quite easy to imagine that a service overprovisions to account for people not being required to accept a "page". that overprovisioning specifically is so that people can hold multiple on-call type jobs simultaneously.

But I think if Uber and Lyft are required to pay their employees an hourly rate they would then require them to respond to every page for their scheduled shift.

They don't now? I'd heard both would boot you from their network if you turn down too many rides.