So people want a social media platform that has broad reach, high availability, (some) algorithmic curation, never ending content, moderation, first-class mobile support, but aren't willing to pay for it in any way (ads or subscriptions). This is precisely why I don't see anyone replacing Reddit. Niche communities will continue to exist and thrive on the internet but the mega social media aggregators like twitter, reddit, etc only seem to be viable (who knows for how long) with the same old business model: ads and VC money.