There's a definite network effect... its hard to justify riding a shared bike somewhere if you can't be reasonably sure there will be one for you to ride back when its time to return. Maybe you could cobble a trip together with multiple vendors in cities where there are competing systems, but thats more hassle and makes it difficult if you're buying a yearly pass or some other monthly discount.
If you want some real data from a large program with good public support, CitiBike in NYC publishes open ridership data: https://www.citibikenyc.com/system-data
The tl;dr is that the system is very popular, and they're constantly expanding it - currently averaging around 62k trips per day on 12k bikes across 750 stations.
I own my own bike, but I'll use a Citibike for a one-way trip or to bridge a gap when I'm already out away from home without my bike. There is also a ton of utility for people who ride more casually, or don't want to carry bikes up stairs, or don't have room in their apartment, etc, etc.
If you want some real data from a large program with good public support, CitiBike in NYC publishes open ridership data: https://www.citibikenyc.com/system-data
The tl;dr is that the system is very popular, and they're constantly expanding it - currently averaging around 62k trips per day on 12k bikes across 750 stations.
I own my own bike, but I'll use a Citibike for a one-way trip or to bridge a gap when I'm already out away from home without my bike. There is also a ton of utility for people who ride more casually, or don't want to carry bikes up stairs, or don't have room in their apartment, etc, etc.