Innovation isn't the only thing that leads to success, not by a long shot. Polish, ease of use, a large feature set, security, and any number of other factors can have just as big an impact on users as innovation.
People don't use Google search because it's innovative, and people don't use Facebook because it innovated and people won't make their decisions on Google+ based on its innovations.
People don't use Google search because it's innovative, and people don't use Facebook because it innovated and people won't make their decisions on Google+ based on its innovations.