In an article from December 2015 on Wharton Knowledge – The Sharing Economy: A New Way of Doing Business, there are really good insights into the motivation to create sharing solutions and the success of such solutions.

At least until recently, car buyers haven’t worried about the excess capacity they were purchasing, as long as the lifetime value of the vehicle was greater for them than its lifetime cost.
……
“In the collaborative economy it’s not the idea of sharing that’s new… What’s different now is the introduction of technology into the concept.” — H.O. Maycotte, Umbel

All this excess capacity is what makes the sharing economy possible.
……
“Consumers simply want to make savvy purchases, and access economy companies allow them to achieve this, by offering more convenience at lower price.” — Giana M. Eckhardt and Fleura Bardhi, researchers