I introduced kbin to someone today who asked what the fediverse was. I answered for them of course, but it made me realize that the concept is still technobabble for most people. The average joe probably doesn’t care or notice that server A is really talking to server B. Just have them find out on their own and if a mass migration does need to happen from A to B, just make a standard announcement.
I’m not too worried about the learning curve. I can remember when explaining Reddit to my friends ended in a blank stare. I also encountered plenty of people on Reddit, even recently, who were only there for a specific sub and had no real awareness of the larger Reddit system/community.
The same thing can happen with the Fediverse. Communities on specific instances will gain critical mass and attract people from outside the Fediverse, who will sign up and engage with what they think of as just another website.