Seems a bit disingenuous to compare the niche of tech folks that used Google+ to the niche that use WeChat, with the later "niche" being... China...
Not everyone has to agree that dominating a country's social media usage is a good goal, but it clearly is the goal for many companies, and they're going to continue to persue it. Perhaps users of social media should redefine success, but for creators of social media platforms there are absolutely clearly defined measures of success and failure.