Over my career, I worked on many different mainframe systems (IBM "big iron") and with many different commercial applications. No matter which system or application, we were always involved (either passively or actively) with the associated "user group".
For IBM systems (both hardware and software), it was "Guide" (http://en.wikipedia.org/wiki/GUIDE_International) and "Share" (http://en.wikipedia.org/wiki/SHARE_%28computing%29). Other applications and services had their own user groups.
I can't comment on the trend to dispensing with vendor-support in favour of user-group support, but I can assure you that user-group support has (for decades) been a staple in the industry.