However, what isn't covered (and this is especially pertinent for ride sharing) is the time between ending a job and taking the next job.

While I wouldn't expect anything like full-time pay, Uber/Lyft et. al. still get a benefit of having drivers on call (lower wait times for their customers). I personally would have liked to see some compensation (within reason) for time spent on call but not on a ride. Not sure how easy it would be to make both a fair and reasonably un-cheatable system, but its something that should have been considered.