Since Twitter was recently acquired by the wealthiest person on Earth, a 'decentralized' social network called Mastodon became especially popular amongst those willing to replace Twitter by a more sustainable app. This article aims to describe why I strongly believe that Mastodon (as it is today) wont ever be a sustainable and popular (100 M+ daily active users) alternative to social media. Apps based on the groundbreaking Authenticated Transfer (AT) Protocol (e.g, Bluesky) might be the solution we need.