That's because the asymmetry of the one-way publication funnel where we can only consume has been replaced by a more symmetric ecosystem where users contribute

That's because the asymmetry of the one-way publication funnel where we can only consume has been replaced by a more symmetric ecosystem where users contribute content. Because they donate their content to platforms, they make the platform owners rich - they get the attention, so they also get the ad revenue, but they don't need to pay for quality content because users are just fine with (other) users' contributed content. If there had been zero-install tools for self-publishing early on instead of the centralized Facebooks and Mediums, perhaps things could have gone differently.