I think when Matt says "long-term consistency with core" he also means consistency with the philosophical aspects of free software. Note that the piece starts with Facebook's reaction to the Apache Foundation's stance against using React.
If I understand correctly, the Calypso project was related to the administrative dashboard in their hosted WP offering (and other widgets that could be used in self-hosted WP.) Going forward it looks like Gutenberg is also about the code in the pages that visitors see on published sites.
Gutenberg will be distributed with WordPress itself as the new post editor. This means the license(s) used with it will then apply to users of WordPress, who may or may not want to agree with React's license despite Automattic (WordPress.com) being comfortable with it via Calypso (WP.com's front end).
If I understand correctly, the Calypso project was related to the administrative dashboard in their hosted WP offering (and other widgets that could be used in self-hosted WP.) Going forward it looks like Gutenberg is also about the code in the pages that visitors see on published sites.