Decentralization fundamentally changes the business model of running a social network because it dramatically reduces operating costs. It absolves a single entity of having to shoulder all operating costs alone, as no single server needs to grow beyond its comfort zone and financial capacity. Furthermore the entry cost is near zero, which means an operator of a Mastodon server does not need to seek venture capital or other forms of investment which would pressure them to use large-scale monetization schemes. There is a reason why the $1 per year business model of WhatsApp was rejected by Facebook executives after its acquisition: It is sustainable and fair, but it does not provide the same unpredictable, potentially unbound return of investement that makes stock prices go up as advertising does.