It’s a great video but it overemphasis the ubiquitousness of interoperability quite a lot. But its still good to see a well designed campaign video on the subject.

I think, as well as the issues you mention, another issue might possibly be duplication. Historically, search engines penalise duplicated content, even across different domains and federation kind of bakes that in.

In my own personal experience, Nextcloud;

• Needs constant attention to prevent falling over
• Administration is a mess
• Takes far too long to get used to its ‘little ways’
• Basics like E2EE don’t work
• Sync works when it feels like it
• Updating feels like russian roulette