Here is a small scale example of one of the challenges of public/private partnerships--the Uptown Parklet in Seattle, WA, USA.
The parklet was first envisioned in 2012 and, after fundraising, was installed in February 2015. In October 2015, the parklet was removed. The main reason for removal was the failure to establish and fund an adequate program for maintaining the parklet. See below for two articles that offer background and perspective on what took place.
Meet the Uptown Parklet (SEATTLE REFINED - February 21, 2015)
http://seattlerefined.com/lifestyle/meet-the-uptown-parkletUptown Alliance Removes Parklet (QUEEN ANNE & MAGNOLIA NEWS - October 20, 2018)
https://queenannenews.com/…/Uptown-Alliance-re…/26/337/39885
Top - Parklet concept from 2012. Lower left - Parklet opening in Feburay 2015. Lower right - Parklet removed in October 2018.