Problem with Reddit is being very replaceable. People don't want to lose their facebook/instagram/linkedin page because it has their content and also personal connections. Profiles on Reddit are more like Digg / Slashdot / Kuro5hin - few care about losing their post history and connections so when a competing site comes in with better features (fewer ads / different site-wide moderation approach / not looking so awful by default ) people will just move there.