I am extremely skeptical of 2 and 3, because it means people who already decided to drop mainstream social media platforms will go back on their decision, and it suggests that people want instances to be more like Meta, rather than for it to function in a user driven way that provides things that Meta will never be willing to offer.
If people can be tempted off of the Fediverse so easily, the problem is not Meta. Keep in mind that right now people are already choosing not to engage with Facebook. I'm not naive to assume that they won't have appeal and influence and dirty tricks. but seems to me like such a complete lack of faith in the Fediverse to assume that if Meta merely exists alongside the ecosystem, it's inevitable that everyone will jump ship. That sounds like what they wanted was a Big Tech-driven platform all along.
I don't think that's right.
Comes to mind also that Mastodon has had many years of headstart. How much of a slow growth does it still need?