I have step 6. for you - big giants come into the fediverse, you have meta, google, microsoft or whoever else. In the eyes of users these become the main legit instances in the same way that gmail. hotmail, protonmail became for email. Everyone else is blocked by default for safety reasons, or refuses to use the AP that is now dictated by meta or google, or overwhelmed by the amount of traffic or straight up spam and bots and so users just go with the path of least resistance and create their accounts on the "legit", "safe", instances where all the biggest, popular communities exist anyway. The (ad)free fediverse remains a niche and we who stay on it look like the "old man yelling at cloud" meme.

But I'm a pessimist, who knows what will happen. A month ago I had no idea this place even existed so I'm not that clever of a person, time will tell. I think the best thing we can do is establish our unified presence on the fediverse before meta gets to do it, then they can't dictate the tempo.