It's funny how this is always presented as some sort of natural process when in fact there are marketing people in Big Tech whose main job is effectively to find ways to get people off those independent platforms. There is only so much time in a day and you can only browse one thing at a time. Every minute you spend on some forum is a minute you're not engaging with Facebook/Twitter/YouTube/etc. Do you really think they're indifferent and neutral towards third party platforms?