Uber is "ride sharing" like hiring a carpenter is "hammer sharing."
I hate the way that any company with a vaguely peer-to-peer business model calls themselves 'sharing', or 'part of the sharing economy'. It's not just Uber. e.g. Zopa (a p2p loans company) describes itself as 'sharing', but it's a business where people lend money to others for a fee. AirBnB claims to be 'sharing', but at it's core, it is little more than a hotel booking system. Taskrabbit gets described as 'part of the sharing economy' but no-one is sharing anything, you are paying for workers to do chores.
Since when has sharing involved making a profit by charging users?
The behavior isn't even limited to tech startups.
In contrast, Uber is not like AirBnB. It sets the rates for drivers, requires certain cars, etc. If Uber really was like AirBnB overall, it'd be a different story.
In addition, "ride sharing" also refers to the transportation itself as a shared resource, in the same way as a taxi, or even public transportation. With a system of shared transportation, not everyone needs their own vehicle which has significant financial/economic and environmental implications.
tl;dr: Uber/Lyft are shared resources among people who may or may not actually be in the car together at the same time—and the resource they are sharing is transportation ("rides").
This is no longer true with Uber Pool and Lyft Line
I beg to differ. I just took an UberX from Changi Airport to home, a 30 minute ride during which the driver took on and dropped off a total of 3 other passengers.
The cost was about half the taxi rate.
Van services for the airport have existed for a long time, in which they do multiple stops for the different passengers, and yield the same cost-savings against taxis, but no one would call that ride-sharing.
The problem with Blablacar-type apps is flexibility, unless you're doing a very common trip you'll find yourself having to be very flexible with hours and pickup and drop-off points. On the upside, it's much cheaper than alternatives especially for trip between cities.
Uber's model of having drivers basically work at as close to full capacity as possible most of the time is excellent and a great way to reduce congestion at the heart of cities, or even just the demand for parking lots.
Vans get us into the implementation, rather than the model. The model is that if there are spare seats they should be filled. The implementation is the type of car being used. I suspect that if vans were profitable for Uber Pooling they would be much more used by now, but the optimal size seems to be the family sedan or the small SUV, at least in Singapore. They might make more sense in frequent suburb -> CBD type trips where there is a lot of demand for the same trip at the same time, although in the situations where I've needed to do such a trip, there's always been frequent express buses or direct trains provided by the city (e.g. in Sydney from the North West suburbs to Darling Harbour).