Until your home instance defederates from another instance. Sure, you can always make another account, but your average user wants a lower friction experience.
I'm reasonably active in the fediverse, but I recognize that the more explaining it takes to the average user the less likely they're going to want to join in.
The old old top gear cool wall tried to hit on this concept. You could have a very technically excellent car classified as uncool because if you had to explain why it was cool to a normie you had already lost them.
It will be hard for the fediverse to get over this hump, which is probably why you see so many Linux users here and so few say woodworkers or other (somewhat) more niche communities.