It's not only the break in routine but also the direction of the site. All your examples are productivity products while the fediverse is, in essence, social media. The thing with social media is that branding REALLY matters. There have been attempts to copy Instagram or Snapchat or Reddit but they have all failed to gain massive communities due to not being part of a known brand.
"I posted my pics on the gram"
"What's your snap?" etc....
Kbin, Lemmy, these are just instances of something called the Fediverse, try getting a layperson to understand that.
Social media generally has a rule known as the 90:9:1 rule. 90% of people are lurkers just doomscrolling or passing time, 9% are interacting with content and leaving comments and/or posting, and the final 1% is making the engaging content that sites like Reddit and YouTube are known for.
Right now, FOSS software is often populated by only 10% of that ratio, the power-users and people that interact every so often. Those lurkers, the 90%, migrating them will be hard if not impossible. Remember, they lurk, they will stay where the most engaging content is, and that is still currently Reddit.
You're acting like any government, American or no, can handle the security aspects of a national database. Also, what's the point? Using an ID to play games, to watch porn? That shit is dumb, you can't nationalize or control the internet in any form, even with ID specifications. It's just not a realistic goal