[DrScump]

  store them with ease at the side of the street; perhaps paying a fee while they use the land

Then it's no longer a sharing model; it's a "I want 24/7 control of a bike but only pay for while I'm riding it and park it anywhere without consequences" model.

Which would be handy, but it wouldn't scale well from a business standpoint.

[CalRobert]

For what it's worth that is exactly how car sharing works in my city and it's doing well, and growing.