It’s a shame kbin.social is no more. I guess Fedia.io is as big as it gets now.

As far as I’m aware, the big “problem” with Mastodon (and the Fediverse as a whole) is that you have to choose an instance to join. It’s an aditional step that mainstream social media does not have and it’s already enough to push regular people away. It’s kinda like trying to convince a Windows user to jump ship to Linux, by the time you begin explaining what a distro is you’ve already lost them.