Seems like Hitch is to Uber/Lyft as Casual Carpool is to taxis. Is that accurate?
While are drivers are for-hire at this phase (in order to provide a reliable and available supply-side), there is much higher utilization in the car as multiple riding parties are paired to it.
EDIT:
I see the question was changed slightly. Higher utilization makes all the difference. Our current public transit system is just as you've stated: a vehicle being shared by "more strangers" (in your own words). We envision our system creating a completely adaptive and dynamic transit grid, which lends itself to predominant way in which people get around in the future.